APPENDIX G

On the Mountain Flora of Two Valleys in the Great Atlas of Marocco.

By John Ball.

Although an attempt to discuss the character and relations of the Flora of a region so wide and so little known as the mountain region of the Great Atlas would as yet be quite premature, it appears that the materials at our disposal suffice for an examination of the vegetation of the valleys lying south and south-west of the city of Marocco, which may be an acceptable contribution to botanical geography. For this purpose it seems best to limit the discussion to the two valleys where our collections were sufficiently extensive to give a tolerably complete representation of the vegetation, as far as this was developed at the season of our visit, and to exclude altogether the plants found along the skirts of the great range below the level of about 1,200 metres above the sea. The Flora of the zone below that level is largely mixed up with extraneous elements, represented by plants of the low country that reach the base of the mountains, but do not penetrate the interior valleys, and if these had been admitted the special features of the mountain Flora would have become less apparent. The plants collected in the course of a somewhat hurried excursion from Seksaoua, when we reached a height of about 1,600 metres, have been designedly omitted. On such occasions attention is to a great extent monopolised by the new and rare species not hitherto seen in the same region, while comparatively familiar forms are less carefully noted. Collections made under such circumstances rarely give a moderately complete report of the vegetable population.

In ascending to the higher region of mountains that approach to the limit of vegetation the absolute number of species is so much smaller that this source of error is far less apparent; and it is not likely that in the two ascents which we made to the dividing ridge of the Atlas many species that came within our range of vision were overlooked. The following tabular arrangement shows that in the Aït Mesan valley, where we spent the greater part of six days, we collected 375 species of phænogamous plants, to which have been added three subsequently found there by MM. Rein and Fritsch; while in the Amsmiz valley only 223 species—or less than three-fifths of the above number—were collected. Of these 146 species are common to both valleys; so that our list does not in all exceed 455 species of flowering plants, to which I have added 10 vascular cryptogams, of which two only were found in the Amsmiz valley.

In the following list I distinguish a middle zone, extending from 1,200 to 2,000 metres above the sea, and a superior zone including all above that limit; the latter corresponding pretty nearly with the sub-alpine and alpine zones of the higher mountains of Europe. With reference to their distribution I have divided the species into four categories: 1, Mid-European, those extending to Central Europe, of which more than three-fourths belong to the British Flora: 2, wide-spread Mediterranean, extending beyond the bounds of the three adjoining regions, Algeria, the Spanish peninsula, and the Canary Islands: 3, confined to adjoining regions; that is, to one or more of those just enumerated: 4, endemic, known only in the Great Atlas, or the neighbouring provinces of Marocco.

Tabular View of the Mountain Flora of the Great Atlas, showing the distribution of the Species found in the Valleys of Aït Mesan and Amsmiz. S indicates the superior zone from 2,000 m. to 3,500 m. above the sea; M the middle (or mountain) zone, from 1,200 m. to 2,000 m.

Name of Species Aït Mesan Amsmiz Mid-European Wide-spread Mediterranean Confined to adjoining regions Endemic

Ranunculus spicatus, L. var. — S — — * —

„ atlanticus, Ball M M — — *

„ bulbosus, L. var. M M * — —

„ arvensis, L. M S — * — —

„ muricatus, L. — M — * — —

„ Reinii, nov. sp. S — — — — *

Aquilegia vulgaris, L. var. — M * — — —

Delphinium Balansæ, B. et R. var.? S S — — * —

Berberis cretica, L. var. — S — * — —

Papaver tenue, Ball M S M S — — — *

„ rupifragum, B. et R. var. S S — — * —

Rœmeria hybrida, D.C. — M — * — —

Hypecoum pendulum, L. M — * —

Corydalis heterocarpa (Dur.) M — — — *

Fumaria officinalis, L. S — * — — —

„ parviflora, Lam. M M * — — —

„ media, Lois var. M — * — — —

„ agraria, Lag. var. M — — * — —

„ tenuisecta, Ball. M — — — — *

Nasturtium officinale, R. Br. S — * — — —

„ atlanticum, Ball S — — — — *

Arabis albida, Stev. S — — * — —

„ erubescens, Ball S — — *

„ auriculata, Lam. S S * — — —

„ decumbens, Ball S S — — *

„ conringioides, Ball S S — *

Cardamine hirsuta, L. var. — S * — —

Alyssum alpestre, L. vars. M M * —

„ montanum, L. var. S * — —

„ campestre, L. M S — * —

„ calycinum, L. M S — * — —

„ spinosum, L. S — — * —

Draba hispanica, Boiss. — S — — *

Sisymbrium Thalianum S * — —

„ runcinatum, Lag. var. — M — — *

Erysimum australe, Gay, var, M S M S * — — —

Brassica rerayensis, Ball S — — — *

Capsella bursa-pastoris, L. S — * — — —

Lepidium nebrodense, Raf. var. S — * —

Biscutella lyrata, L. var. S — — * — —

Thlaspi perfoliatum, L. et var. S S * — —

Hutchinsia petræa, R. Br. S S * — —

Isatis tinctoria, L. var. M M * — —

Crambe hispanica, L. — M — * —

Capparis spinosa, L. M — — * —

Reseda attenuata, Ball S — — *

„ phyteuma, L. M * — —

„ lanceolata, Lag. M — — *

Cistus polymorphus, Willd. M — — *

Helianthemum niloticum, L. var.? S — — * —

„ rubellum, Presl. — M * —

„ glaucum, Cav. — M * —

„ virgatum, Desf. et var. M M — — *

Fumana glutinosa, L. M M — * — —

„ calycina, Claus. M — — — * —

Viola tezensis, Ball — S — — — *

Polygala rupestris, Pourr. M M — * —

„ Balansæ, Coss. M M — — — *

Dianthus attenuatus, Sm. M S — — * —

„ virgineus, L. M M * — — —

Tunica compressa, Desf. — M — — * —

„ prolifera, L. M M S * — — —

Silene inflata, Sm. var. M — * — — —

„ nocturna, L. M — * — —

„ corrugata, Ball M — — — *

„ muscipula, L. M * — —

„ italica, L. M M * — —

Holosteum umbellatum, L. S S * — —

Cerastium glomeratum, Thuill. S S * — — —

„ brachypetalum, Desf. S S * — —

„ arvense, L. M S M S * — —

Stellaria media, L. M — * — —

„ uliginosa, Murr. S — * — —

Arenaria pungens, Clem. et var. S S — — *

„ serpyllifolia, L. S S * — —

„ procumbens, Vahl. M — * —

„ fasciculata, Gouan S — * — — —

„ setacea, Thuill. var. S S * — — —

„ verna, L. var. S S * — — —

Buffonia tenuifolia, L. M — — * — —

Sagina procumbens, L. var. S S * — —

„ Linnæi, Prese. S — * — —

Polycarpon tetraphyllum, L. M * — —

„ Bivouæ, J. Gay S S * —

Montia fontana, L. S * — — —

Hypericum perforatum, L. M — * — — —

„ coadunatum, Chr. Sm. var. M — — — * —

Malva sylvestris, L. M — * —

„ rotundifolia, L. M S — * — —

Linum corymbiferum, Desf. M — — — * —

Fagonia cretica, L. M — — * — —

Geranium malvæflorum, B. et R. S S — — * —

„ pyrenaicum, L. M M * — — —

„ molle, L. S — * — — —

„ rotundifolium, L. M M * — — —

„ lucidum, L. S M S * — — —

„ robertianum, L. var. M — * — — —

Erodium Jacquinianum, F. et M. M S — * — —

„ malacoides, L. M — — * —

„ guttatum, W. M — — — * —

Oxalis corniculata, L. M — * — —

Ruta chalepensis, L. M S — — * —

Rhamnus Alaternus, L. M M — * — —

„ lycioides, L. — M — — *

Acer monspessulanum, L. M — * — — —

Pistacia Lentiscus, L. M M — * — —

Lotononis maroccana, Ball M M — — *

Argyrolobium Linnæanum, Walp. var. M S — — * —

„ stipulaceum, Ball — M — — — *

Adenocarpus anagyrifolius, Coss. M M — — — *

Genista dasycarpa (Coss.) M — — — — *

„ myriantha, Ball M — — — *

„ florida, L. var. M — — — * —

Cytisus Balansæ, Boiss. var. S S — — * —

„ albidus, D.C. — M — — — *

„ Fontanesii, Spach M — — — * —

Ononis atlantica, Ball — M — — — *

„ antiquorum, L. — M — * — —

Trigonella monspeliaca, L. M — * — —

„ polycerata, L. et var. S M — — * —

Medicago lupulina, L. M — * — — —

„ suffruticosa, Ram. S S — — * —

„ turbinata, W. vars. M M — * — —

„ denticulata, W. — M * — — —

„ minima, Lam. M — * — — —

Melilotus indica, All. M — — * — —

Trifolium atlanticum, Ball S — — — *

„ glomeratum, L. var. S — * — — —

„ repens, L. M — * — —

„ humile, Ball S *

„ tomentosum, L. M — * —

Anthyllis Vulneraria, L. et var. M S — * — — —

„ tetraphylla, L. M — — * — —

Lotus cytisoides, D. C. M — — * —

Coronilla pentaphylla, Desf. M — — — *

„ ramosissima, Ball M — — — *

„ minima, L. M — * — —

„ scorpioides, L. M — — * — —

Hippocrepis atlantica, Ball S — — — *

„ multisiliquosa, L. var. M — — * — —

Psoralea bituminosa, L. M — — * — —

Colutea arborescens, L. M — * — — —

Astragalus sesameus, L. M — — * — —

„ Reinii, Ball S — — — — *

„ Glaux, L. var. M — — — * —

„ atlanticus, Ball M — — — — *

„ ochroleucus, Coss. S — — — — *

„ incurvus, Desf. M — — — *

Vicia onobrychoides, L. S — — * — —

„ glauca, Presl. var. S — — * —

„ sativa, L. vars. M S — * — — —

Lathyrus aphaca, L. M — * — — —

„ sphæricus, Retz. M — * —

Ceratonia siliqua, L. M M * — —

Prunus prostrata (Labill.) S S * — —

Poterium sanguisorba, L. M * — — —

„ verrucosum, Ehrnb. var. M — * — —

„ anceps, Ball S S — — — *

„ ancistroides, Desf. M — — *

Rosa canina, L. var. M M * — —

„ Seraphini, Viv. S S — * — —

Saxifraga globulifera, Desf. M S M S — * —

„ tridactylites, L. S * — — —

„ granulata, L. S S * — — —

Ribes Grossularia, L. M S S * — —

Cotyledon umbilicus, L. M M * — — —

Sedum modestum, Ball M M — — — *

„ dasyphyllum, L. var. M M * — — —

„ acre, L. M S M S * — — —

Sempervivum atlanticum, Ball M — — — — *

Monanthes atlantica, Ball — S — — — *

Bryonia dioïca, Jacq. M — * — —

Eryngium Bourgati, Gouan, var. — S — — * —

„ variifolium, Coss. M — — — *

Bupleurum spinosum, L. S S — * —

„ acutifolium, Coss. M M — — * —

„ oblongifolium, Ball M — — — *

„ lateriflorum, Coss. M — — — *

Deverra scoparia, Coss. et Dur. — M — — * —

Carum mauritanicum, B. et R. M M — — * —

Pimpinella Tragium, Vill. M — — * — —

Tinguarra sicula, L. — M — * — —

Scandix pecten Veneris, L. M — * — — —

Kundmannia sicula, L. M — * — —

Meum atlanticum, Coss. S — — *

Heracleum Sphondylium, L. S * — —

Bifora testiculata, L. M — — * — —

Caucalis latifolia, L. M — * — — —

„ daucoides, L. — M * — — —

„ leptophylla, L. M S M — * — —

„ cœrulescens, Boiss. M — — — * —

Elæoselinum meoides, Desf. M — — * — —

Hedera Helix, L. M — * — — —

Sambucus nigra, L. M M * — — —

Viburnum Tinus, L. — M — * — —

Lonicera etrusca, Santi M — * — —

Putoria calabrica, L. M — — * — —

Callipeltis cucullaria, L. — M — * — —

Rubia tinctorum, L. S — * —

„ peregrina, L. et var. M — * — —

Galium Poiretianum, Ball M — — — * —

„ corrudæfolium, Vill. — S — * — —

„ sylvestre, Poll. var. S — * — — —

„ acuminatum, Ball M S — — — *

„ noli-tangere, Ball — M — — — *

„ tunetanum, Lam. M — — — * —

„ parisiense, L. var. M S M S * — — —

„ tricorne, With. S M * — — —

„ spurium, L. M S S * — — —

„ murale, L. — M — * — —

Asperula aristata, L. var. M * — —

„ hirsuta, Desf. M — — — * —

Crucianella angustifolia, L. M * — —

Sherardia arvensis, L. M — * — —

Centranthus angustifolius, D. C. M S — * —

„ calcitrapa, L. S S — *

Valerianella discoidea, W. M — — * — —

„ auricula, D. C. M S M * — —

„ carinata, Loisel. — M * — —

Scabiosa stellata, L. M — — * — —

Pterocephalus depressus, Coss. M S M — — — *

Bellis annua, L. var. — M — * — —

„ cœrulescens, Coss. M S M S — — *

Evax Heldreichii, Parl. S * — —

Micropus bombycinus, Lag. M M — * —

Filago germanica, L. var. — M * —

„ heterantha, Rafin. S S — * — —

Filago gallica, L. M M * — — —

Phagnalon saxatile, L. M M — * — —

„ atlanticum, Ball M — — — — *

Gnaphalium luteo-album, L. M M * — —

„ helichrysoides, Ball S — — — *

Inula montana, L. M — *

Pulicaria mauritanica, Coss. M — — — *

Odontospermum aquaticum, L. M — — * — —

Anacyclus depressus, Ball S — — — *

„ valentinus, L. — M — * — —

Achillea ligustica, All. et var. M M — * —

Anthemis tuberculata, Boiss. — S — *

„ heterophylla (Coss.). M M — — *

Chrysanthemum Gayanum (Coss.) et var. M S M S — — * —

„ atlanticum, Ball S S — — — *

„ Catananche, Ball S S — — — *

Senecio lividus, L. var. S — — * — —

„ giganteus, Desf. M M — — * —

Calendula maroccana, Ball M M — — — *

Echinops spinosus, L. M — — * —

Xeranthemum modestum, Ball M M — — — *

Atractylis cancellata, L. M M — * — —

„ macrophylla, Desf. M — — — * —

Carduus macrocephalus, Desf. M — — * — —

„ Ballii, H. fil. M S M — — — *

Cnicus echinatus Desf. M — — * — —

„ ornatus, Ball — M — — — *

„ chrysacanthus, Ball M — — *

„ Casabonæ, L. S — — * — —

Stæhelina dubia, L. var. — M * — —

Centaurea incana, Desf. var. M — * — —

„ Salmantica, L. var. M M * — —

Carthamus cœruleus, L. var. M S — — * — —

Carduncellus lucens, Ball M S — — — — *

Catananche cærulea, L. et var. M M — * — —

„ cæspitosa, Desf. — S — * —

Tolpis umbellata, Bert. M — — * —

Rhagadiolus stellatus, L. M M — *

Crepis taraxacifolia, Thuil. var. M * —

„ Hookeriana, Ball — S — — — *

Phæcasium pulchrum, L. S S * — — —

Hieracium Pilosella, L. S S * —

Hypochæris glabra, L. var. M — * — — —

„ leontodontoides, Ball S — — — *

Leontodon autumnalis, L. var. S — * — —

„ Rothii, Ball M M * —

„ helminthioides, Coss. — M — — *

Taraxacum officinale, Wigg. var. S S — * — —

Lactuca viminea, L. M — — — *

„ tenerrima, Pourr. M M * —

„ saligna, L. M — * —

Sonchus oleraceus, L. — M — * —

„ asper, Vill. M — * —

Microrhynchus nudicaulis, L. M — * — — —

„ spinosus (Forsk.) M — * — — —

Scorzonera undulata, Vahl. M — — * — —

„ pygmæa, S. et S. S — — * —

Jasione atlantica, Ball S — — — * —

Campanula maroccana, Ball M — — * —

„ rapunculus, L. M — — — — *

„ Lœfflingii, Brot. M — — — *

Specularia falcata (Ten.) — M * — —

Trachelium angustifolium, Schousb. M — — * —

Arbutus Unedo, L. M * —

Armeria plantaginea (All.)? S — — — *

Asterolinum linum-stellatum, L. — M * — — —

Anagallis linifolia, L. et var. M S — * — — —

Jasminium fruticans, L. M — — * — —

Fraxinus oxyphylla, M. B. M M — * — —

„ dimorpha, Coss. et Dur. M — — * —

Phillyrea media, L. M M — * —

Olea europæa, L. M M — * —

Nerium Oleander, L. M M — * — —

Convolvulus Cantabrica, L. M M * — —

„ undulatus, Cav. M — — * — —

„ sabatius, Viv. var. M S — — * — —

„ siculus, L. — M — * — —

„ althæoides, L. M — * — —

Hyoscyamus albus, L. M — — * — —

Anchusa atlantica, Ball M — — * — —

Lithospermum arvense, L. S — * — —

„ incrassatum, Guss. var. S M S — — *

„ apulum, Vahl. M * — —

Myosotis sylvatica, Hoffm. var. S S — * — —

„ hispida, Schlecht. var. S — — * — —

„ stricta, Link S S * — — —

Cynoglossum Dioscoridis, Vill. et var. M S — * — — —

Rochelia stellulata M M * — — —

Verbascum calycinum, Ball M — * — —

Celsia maroccana, Ball M — — — *

Linaria ventricosa, Coss. M M — — *

Linaria heterophylla, Desf. M M — * — —

„ galioides, Ball et var. S — — — — *

„ arvensis, L. var. S M S — * — —

„ marginata, Desf. S — — — * —

„ lurida, Ball S — — *

„ Munbyana, Boiss. et Reut. M — — — * —

„ Tournefortii (Poir.) S S — — * —

„ rubrifolia, Rob. et Cast. M — — * — —

Anarrhinum pedatum, Desf. M — — — * —

„ fruticosum, Desf. — M * — —

Scrophularia canina, L. var.? — M * — — —

Digitalis lutea, L. var. M — * — —

Veronica Beccabunga, L. S — * — — —

„ cuneifolia, Don. var. S S — * — —

„ arvensis L. et var. S S * — — —

„ triphyllos, L. — M * — —

„ agrestis, L. S — * — —

„ hederifolia, L. et var. M S M S * — —

Phelipæa cærulea, Vill. M * — — —

Orobanche Hookeriana, Ball M — — — — *

„ barbata, Poir. M — — — * —

Lavandula dentata, L. et var. M M — * — —

„ tenuisecta, Coss. M S M S — — — *

Mentha rotundifolia, L. S — * — — —

Thymus saturejoides, Coss. et var. M M — — — *

Thymus Serpyllum, L. var. S — * — —

„ lanceolatus, Desf. var. M M — * — —

„ maroccanus, Ball M — — — — *

Micromeria microphylla, Benth M — — * —

Calamintha graveolens, M. B. M — — * — —

„ alpina, L. var. S S * — — —

„ atlantica, Ball M S M S — * —

Hyssopus officinalis, L. S S * — — —

Salvia Maurorum, Ball — M — — — *

„ clandestina, L. var. M S — * — —

Nepeta multibracteata, Desf. M — — * —

„ atlantica, Ball — M — — *

Sideritis villosa, Coss. M S M S — — *

„ scordioides, L. var. S * — — —

Lamium amplexicaule, L. M S M S * — — —

„ album, L. var. M — * — —

Teucrium granatense, B. et R. var. — M — — * —

„ polium, L. vars. M M — * — —

Ajuga Iva, L. M S M S — * —

Globularia Alypum, L. — M — * — —

Plantago albicans, L. var. — M — * — —

Plantago coronopus, L. var. M S M * — — —

„ mauritanica, B. et R. — M — — *

Paronychia argentea, Lam. M S M S — * — —

„ capitata, Lam. var. M S * —

„ macrosepala, Boiss. et var. M — * — —

Scleranthus annuus, L. var. S * —

Polycnemum Fontanesii, Dur. et Moq. M — — — *

Rumex scutatus, L. var. M S — * — —

„ Papilio, Coss. M — — — — *

Polygonum aviculare, L. * — — —

Daphne Gnidium, L. M M — * — —

„ Laureola, L. M — * — — —

Thymelæa virgata, Endl. var. M M — — * —

Osyris alba, L. — M — * — —

Aristolochia Pistolochia, L. M — — * — —

Euphorbia rimarum, Coss. M M — — — *

Quercus Ilex, L. et var. M M S — * — —

Salix purpurea, L. var. M — * — — —

Populus alba, L. var. M M * — — —

„ nigra, L. M — * — — —

Ephedra altissima, Desf. M — — * — —

„ procera, F. et M. M — * — —

Pinus halepensis, Mill. — M — * — —

Callitris quadrivalvis, Vent. M M — — * —

Juniperus oxycedrus, L. M M * —

„ phœnicea, L. et var. M * — —

„ thurifera, L. S * —

Orchis pyramidalis, L. M — * — — —

„ latifolia, L. S — * — — —

Ophrys apifera, Huds. M — * — — —

Iris germanica, L. M — — * — —

Chamærops humilis, L. M M — * — —

Gagea foliosa, Schult. — S — * — —

Muscari comosum, L. M M — * — —

Scilla hispanica, Mill. S — — * —

Ornithogalum comosum, L. S * — — —

„ tenuifolium Guss. S * — —

„ orthophyllum, Ten. M * — —

„ pyrenaicum, L. var. — M * — — —

Allium paniculatum, L. var. — M * — —

Asphodelus microcarpus, Viv. M — * — —

Anthericum Liliago, L. var. M * — —

Colchicum Civonæ, Guss. — S — * —

„ arenarium W. K. var. ? S — *? — —

Smilax mauritanica, Desf. M — — * —

Asparagus acutifolius, L. M — — * —

„ scoparius, Lowe? M — — — *

Juncus bufonius, L. M M * — — —

Scirpus Savii, S. et M. M — * — — —

Carex Halleriana, Asso. — M * — — —

„ ambigua, Link. M — — — * —

„ fissirostris, Ball S M S — — — *

Phalaris nodosa, L. M — — * — —

Piptatherum cœrulescens, Desf. M S M — * — —

Stipa parviflora, Desf. M — — * — —

„ gigantea, Lag.? M — — * —

„ nitens, Ball S — — — — *

Agrostis verticillata, Vill. M — — * —

Phragmites communis, Trin. M — * — —

Echinaria capitata, Desf. M S M S * —

Aira caryophyllea, L. M S * — — —

Trisetum flavescens, L. M * — — —

Avena bromoides, Gouan. var. M — * — —

Arrhenatherum elatius. L. — M * — — —

Poa annua, L. M S M * — — —

„ bulbosa, L. M S M S * — — —

„ pratensis, L. M S M S * — —

„ trivialis, L. M S — * — — —

Melica ciliata, L. var. M — * — —

„ Cupani, Guss. var. M S M — * — —

Dactylis glomerata, L. vars. M S M S * — — —

Cynosurus elegans, Desf. M S — * —

Festuca rigida, L. M — * — — —

„ unilateralis, Schrad. var. M — — * —

„ geniculata, L., et var. M M — * —

„ duriuscula, var. S S * — — —

„ arundinacea, Schreb. M M * — — —

Brachypodium pinnatum, L. var. M — * — — —

„ distachyum, L. M M — * — —

Bromus tectorum, L. M S — * — — —

„ madritensis, L. M M * — — —

„ mollis, L. vars. M S M * — —

„ macrostachys, Desf. var. M — — * —

Lolium perenne, L. M — * — — —

Triticum hordeaceum, Coss. et Dur. M — — * —

Secale montanum, Guss. M — * —

Elymus Caput-medusæ, L. var. M — * —

Hordeum murinum, L. M M * — —

Ægilops ovata, L. M M — * — —

„ ventricosa, Tausch. M — — * — —

Andropogon hirtus, L. var. M — — * —

Cistopteris fragilis, Bernh. S S * —

Cheilanthes fragrans, L. M — — *

Pteris aquilina, L. S * —

Asplenium trichomanes, L. M S — * —

„ viride, L. S *

„ Adiantum-nigrum, L. S *

Notochlæna vellea, Desv. M — — *

Ceterach officinarum, Willd. M S M S * —

Equisetum ramosissimum, Desf. M — * — —

Selaginella, rupestris, (Spreng.) M — — * —

Total number of species 465 388 225 161 168 61 75

Before discussing the inferences to be derived from this list, it may be well to notice some sources of error that, to a slight extent, affect the results. Although the season of our visit—the second half of May—was probably the best as regards the middle zone, it was too early to find the vegetation fully developed in the superior zone, especially on the highest ridges. It is probable that on this account the proportion of Umbelliferæ and Gramineæ found in the higher region is smaller than it would have been at a later season. At first sight it would appear that the shorter time that we were able to devote to an examination of the upper region, and the snow-storm which we encountered in the ascent to the Tagherot Pass, make the proportion of species found there, as shown by our lists, unduly small. There can be no doubt that we must have lost several species owing to these causes, but not enough to vitiate the results to a serious extent. In confirmation of this opinion it may be mentioned that although a native employed by M. Cosson has since made a large collection in the same part of the Great Atlas, and two German naturalists—MM. Rein and Fritsch—have visited the head of the Aït Mesan valley, very few species have been added to the Flora of the higher mountain region.

The first conclusion that strikes a botanist on examining the foregoing list is that the general type of the vegetation clearly marks this as belonging to the great Mediterranean Flora, which extends, with local peculiarities, from Persia and Belutschistan to the Atlantic Islands. Out of 248 genera represented in the Flora of these valleys there is not one which is not common to other portions of the Mediterranean region, and one only (Monanthes) is confined to the Great Atlas and the Canary and Cape de Verde Islands, all the others being types more or less widely spread. Further than this, the proportion borne by each of the prevailing natural orders to the whole vegetable population is pretty nearly the same that we are accustomed to find in the mountain regions of the Mediterranean region.

The materials for a comparison are unfortunately yet incomplete as regards many of the mountain districts which are best fitted for the purpose. The Flora of the Lesser Atlas of Algeria, as well as that of the rest of the French possessions in Africa, will be fully known only on the appearance of the important work promised by M. Cosson. The Flora of Spain by MM. Willkomm and Lange is yet unfinished, and there is the further difficulty that those authors have admitted a large number of plants to the rank of species which many botanists reckon only as varieties. M. Boissier’s great work, the ‘Flora Orientalis,’ is also unfinished, and no adequate materials exist for compiling lists of the plants of the Greek mountains, of those of Asia Minor, or of the Lebanon chain, all of which would afford interesting materials for comparison. In the following table I have taken for comparison the Flora of the Sierra Nevada, with the neighbouring mountains of the ancient kingdom of Granada above the level of about 800 metres, compiled from Boissier’s ‘Voyage botanique dans le Midi de l’Espagne;’ that of the Bulgardagh (the principal group of the Cilician Taurus), from a list published by M. Pierre de Tchihatcheff in the ‘Bulletin of the French Botanical Society;’ that of Dalmatia, from Visiani’s excellent ‘Flora Dalmatica;’ and that of the southern slopes of the chain of the Alps from Nice to the Karst, formed by myself from all available sources.

In the same table I have introduced, for the purpose of further comparison, separate columns for the middle and superior regions of the Great Atlas valleys, and in connection with the last I have added in a separate column the results for the higher zone of the Sierra Nevada. Under each heading I have stated

Table. I—Showing the number of species of each of the principal groups and natural orders of plants in two valleys of the Great Atlas compared with other mountain districts in the Mediterranean region.

Gt. Atlas valleys. 455 sp. Middle Zone, Gt. Atlas. 341 sp. Superior Zone, Gt. Atlas. 176 sp. Sierra Nevada, &c., above 800 m. 890 sp. Superior[1] Zone, Sierra Nevada. 486 sp. Bulgardagh. 882 sp. Dalmatia. 2,002 sp. Southern side of the Alps. 2,545 sp.

Dicotyledones 391 86·0 286 83·9 154 87·5 762 85·6 419 86·2 808 91·6 1594 79·6 2035 80·0

Monocotyledones 64 14·0 55 16·1 22 12·5 128 14·4 67 13·8 74 8·4 408 20·4 510 20·0

Compositæ 63 13·8 46 13·5 22 12·5 119 13·4 63 13·0 97 11·0 235 11·7 343 13·5

Leguminosæ 48 10·5 38 11·1 14 8·0 67 7·5 32 6·6 93 10·5 222 11·1 172 6·8

Gramineæ 39 8·6 37 10·8 14 8·0 59 6·6 37 7·6 38 4·3 173 8·6 176 6·9

Caryophylleæ 26 5·7 14 4·1 15 8·5 40 4·5 29 6·0 81 9·2 74 3·7 121 4·8

Cruciferæ 25 5·5 7 2·1 21 11·9 49 5·5 37 7·6 84 9·5 98 4·9 139 5·5

Labiatæ 23 5·0 18 5·3 11 6·3 54 6·1 28 5·8 67 7·0 100 5·0 89 3·5

Scrophularineæ 21 4·6 13 3·8 10 5·7 37 4·2 28 5·8 39 4·4 66 3·3 109 4·3

Umbelliferæ 20 4·4 16 4·7 5 2·8 50 5·6 23 4·7 33 3·7 113 5·6 113 4·4

Rubiaceaæ 18 4·0 15 4·4 7 4·0 20 2·2 12 2·5 19 2·2 26 1·3 34 1·3

Papaveraceæ 10 2·2 8 2·3 3 1·7 10 1·1 6 1·2 12 1·4 14 0·7 14 0·6

Geraniaceaæ 10 2·2 8 2·3 4 2·3 10 1·1 6 1·2 6 0·7 17 0·8 23 0·9

Liliaceæ 10 2·2 6 1·8 4 2·3 15 1·7 9 1·9 23 2·6 61 3·0 52 2·0

Boragineæ 9 2·0 5 1·5 6 3·4 18 2·0 11 2·3 23 2·6 40 2·0 39 1·5

Ranunculaceæ 8 1·8 5 1·5 4 2·3 28 3·1 15 3·1 11 1·2 53 2·6 87 3·4

Cistineæ 7 1·5 6 1·8 1 0·6 23 2·6 10 2·1 1 0·1 11 0·5 10 0·4

Rosaceæ 7 1·5 4 1·2 3 1·7 26 2·6 20 4·1 21 2·4 57 2·8 93 3·7

Campanulaceæ 6 1·3 5 1·5 1 0·6 9 1·0 6 1·2 21 2·4 26 1·3 46 1·8

Convolvulaceæ 5 1·1 5 1·5 1 0·6 3 0·3 2 0·1 4 0·5 10 0·5 9 0·4

Coniferæ 5 1·1 4 1·2 1 0·6 10 1·1 8 1·6 15 1·7 15 0·7 11 0·4

Saxifrageæ (inclusive of Grossulariæ) 4 0·9 4 1·2 4 2·3 12 1·3 9 1·9 2 0·2 9 0·4 52 2·0

Cyperaceæ 4 0·9 4 1·2 1 0·6 17 1·9 12 2·5 7 0·8 43 2·2 119 4·7

Gentianeæ 0 0 0 0 0 0 7 0·8 5 1·0 4 0·5 14 0·07 31 1·2

Primulaceæ 2 0·4 2 0·6 1 0·6 7 0·8 6 1·2 8 0·9 12 0·6 60 2·4

Junceæ 1 0·2 1 0·3 0 0 11 1·2 9 1·9 0 0 8 0·4 31 1·2

the whole number of phanerogamous species included in the Flora of the region, and opposite the name of each natural order I have entered the number of species found in each region, and the percentage proportion which this number bears to the entire flora. Besides the orders which bear the largest proportion in the Great Atlas Flora I have enumerated those that usually characterise the vegetation of high mountains in this part of the world, though several of these are little, or not at all, represented in the Flora of the Great Atlas.

Confining the comparison in the first instance to the figures given for the Atlas Flora as a whole in the first column, and those given in the fourth, sixth, seventh, and eighth columns respectively, for the Sierra Nevada, the Bulgardagh, Dalmatia, and the southern side of the Alps, we remark in the first place that Monocotyledons bear about the same proportion to Dicotyledons in the Great Atlas that they do in the Sierra Nevada, the percentage here being much larger than it is in the Bulgardagh, and considerably less than in Dalmatia or the Southern Alps. In this part of the world this percentage in the Flora of a given region mainly depends upon the number of Gramineæ and Cyperaceæ. The abundance of the latter group in the Alps doubtless arises from the fact that at a former period physical conditions favoured the migration of a large number of northern species that have been unable to extend to the more southern mountain regions of the Mediterranean area.

In all the regions under consideration we find, with a single exception, that the same eight natural orders take precedence of all others as regards the number of species that they exhibit, the aggregate in every case exceeding one-half of the whole phanerogamous Flora. These natural orders are Compositæ, Leguminosæ, Gramineæ, Caryophylleæ, Cruciferæ, Labiatæ, Scrophularineæ, and Umbelliferæ. The exception arises from the prevalence, already noticed, of Cyperaceceæ in the Flora of the Southern Alps. In comparing the figures in the Great Atlas column with those for the other areas above enumerated, it is well to recollect that our materials are taken from a district much more limited in extent than the others, and are necessarily imperfect, because obtained from a single short visit to each valley at a season when many species are yet undeveloped. It is probable, for instance, that the proportion of Umbelliferæ would be increased if the whole Flora were better known. Subject to this remark, it will be seen, as might be expected, that the constituents of the Great Atlas Flora show more analogy with those of the Sierra Nevada and Bulgardagh Floras than with those of Dalmatia and the Southern Alps; but the proportion of Compositæ is larger than in any of them (nearly 14 per cent). In comparing the vegetation of a small district with that of a large one it must be recollected that a small natural group containing a few widely spread species, such as Geraniaceæ, is likely to show a larger percentage proportion to the whole Flora in the small district than in the larger one. It may happen that the same species are spread through both regions; but in one case the number is to be compared with a small total, in the other with a much larger one. This remark has a bearing on the fact that in the Great Atlas Flora the natural orders that bear an unusually large proportion to the total number of the Flora are Leguminosæ, Caryophylleæ, Rubiaceceæ, Papaveraceæ, Geraniaceæ, and Convolvulaceæ. On the other hand, there is a remarkable deficiency in the natural orders that especially characterise the Flora of the Alps, and in a less degree, the high mountains of Southern Europe. These are Ranunculaceceæ, Rosaceæ, Saxifrageæ, Primulaceæ, Junceæ, and Cyperaceæ; not to speak of Gentianeæ, which are here altogether absent.

If, instead of regarding the Atlas Flora as a whole, we examine separately the figures given in the several columns for the middle and superior zones respectively, we find very different proportions for the chief natural orders, except for Compositæ and Leguminosæ which are in both very numerous. In the middle region of the Atlas these two orders represent very nearly one-fourth of the phænogamous Flora. After these Gramineæ, Rubiaceæ, Papaveraceæ, Geraniaceæ, Cistineæ, and Convolvulaceæ are, in the middle region, unusually frequent, while Cruciferæ, Rosaceæ, Boragineæ, and Liliaceæ are remarkably deficient. In the superior zone, on the other hand, the proportion of Compositæ and Leguminosæ is less excessive, making jointly a little over one-fifth of the whole Flora of the upper region. The most marked characteristic here is the very large proportion of Cruciferæ, being less by one species only than the number of Compositæ. Taking into account the number of individuals as well as that of species, this must be regarded as the dominant element in the Flora of the higher region of the Great Atlas, affording as it does 12 per cent of the whole Flora. The only region in which this characteristic is approached is the Bulgardagh in Cilicia, where Cruciferæ supply near one-tenth of the whole list. Caryophylleæ also form an unusually large element in the Flora of the upper zone of the Atlas; but, unlike Cruciferæ, this order exhibits no endemic species, and four-fifths of the whole number are common plants of Central and Northern Europe. Rubiaceæ and Boragineæ have more representative species than is usual in mountain Floras; while there are but three species of Rosaceæ in our list; and Campanulaceæ, Primulaceæ, Coniferæ, and Cyperaceæ are each represented by a single species, and Gentianeæ and Junceæ are altogether absent from the higher zone.

Although statistical results, such as those given above, are not without interest, as throwing light upon the general characteristics of the Flora of a given region, any rational grounds for speculation as to the real affinities and past history of the vegetation must be derived from a closer examination of the individual species of which it is constituted. It is at least conceivable that two Floras should exhibit similar proportions of species belonging to the several natural groups, with no identical species, and with little or no indication of community of origin. The particulars given in our general list will have already led the reader to infer that the results of an examination into the distribution of the individual species that go to make up the Great Atlas exhibit some very peculiar features. Taking the totals at the foot of our list, and excluding cryptogams, it is seen that more than one-third of the species are plants of Middle and Northern Europe, while about one-sixth is made up of endemic species peculiar to Marocco, and, with few exceptions, not known out of the Great Atlas, more than half of the whole list belonging to one or other of these categories. The results, as shown in the following table, are still more remarkable when we separately examine the zones into which mountain vegetation is naturally divided. As in the former table the figures first entered in each column represent the number of species belonging to each category, those next given showing the percentage proportion borne by that number to the total proportion of each region.

Table II.—Showing the distribution of the species of flowering plants included in the Flora of the Great Atlas, and of the Sierra Nevada of Granada,[2] and the Bulgardagh in Cilicia.[3]

Mid-European Wide-spread Mediterranean Confined to adjoining regions Endemic

Great Atlas, including all species found above 1,200 m. 455 sp. 154 33·8 165 36·2 61 13·4 75 16·6

Middle Zone of Atlas, from 1,200 m. to 2,000 m. 341 sp. 106 31·1 141 41·3 46 13·5 48 14·1

Superior Zone of Atlas, from 2,000 m. to 3,500 m. 176 sp. 78 44·3 43 24·4 20 11·4 35 19·9

Superior Zone of Sierra Nevada, above 1,600 m. 486 sp. 209 43·0 74 15·2 104 21·4 99 20·4

Bulgardagh in Cilicia. 882 sp. 159 18·0 359 40·7 157 17·8 207 23·5

From this table we see that while over one-third of the whole Atlas Flora consists of plants of Central and Northern Europe, the proportion reaches nearly to one-half in the higher region (above 2,000 metres); and also that the proportion of endemic species, which in the aggregate is one-sixth of the whole, rises to one-fifth in the upper zone. On the other hand, the proportion of purely Mediterranean species, which amounts to 55 per cent. in the Flora of the middle zone, falls below 36 per cent. in the upper region. Of these Mediterranean species the large majority (more than two-thirds) are widely distributed plants, several of them extending to the mountains of Asia Minor, and twenty species only are exclusively confined to the Great Atlas and to the mountains of Southern Spain, the Lesser Atlas, or the Pyrenees. There is nothing in the distribution of these latter plants to indicate any special connection between the Atlas and any one of the mountain regions above mentioned. Six Atlas species are common to Southern Spain and the Algerian Atlas, six more are known only on the mountains of Southern Spain, five have been hitherto supposed to be peculiar to the Lesser Atlas, and three are elsewhere confined to the Pyrenees.

Some further light may be thrown on the origin of the Great Atlas Flora by considering the affinities of the plants which are reckoned in our list as endemic in Marocco, nearly all being confined, so far as we know, to the chain of the Great Atlas. Although all of these, along with some that we have classed as mere varieties, would be counted as distinct species by many botanists, a considerable number, amounting to more than a quarter of the whole, are, according to the views expressed elsewhere by the writer,[4] to be ranked as sub-species. But here again we fail to discover indications of special relations between the Great Atlas Flora and that of neighbouring mountain regions. Ranking as sub-species twenty-one out of the seventy-five endemic forms enumerated in our list, we find that ten of these are allied to widely spread Mediterranean species, three are related to plants of Central Europe, three to species common to Algeria and Southern Spain, three more to species confined to the Spanish peninsula, and two to endemic Algerian forms.

If we scrutinise in the same manner the endemic forms of the higher region of the Great Atlas, we find that out of the thirty-five enumerated eight, or less than one-fourth, are to be ranked as sub-species. Of these, three are nearly allied to wide-spread Mediterranean species, one to a plant common to Spain and Algeria, two to endemic Spanish species, one to an Algerian endemic form, and one is related to a species indigenous in the Alps and other high mountains of Central Europe.

While recognising the fact that the relations between the vegetable population of the Great Atlas and that of the south of Spain are less close than might have been expected on theoretical grounds, we must yet admit that, on the whole, the Great Atlas is more nearly connected in a botanical sense with this than with any other mountain region that is known to us; and it becomes a matter of some interest to compare closely the list of species obtained by us in the Atlas, with the comparatively well known Flora of Southern Spain. The results of this comparison are given for the Great Atlas generally, and for the superior zone separately, in the following table, in which the Atlas species are distinguished under five heads: 1, those found in the higher region of the Sierra Nevada; 2, in the mountain region of Andalusia; 3, in the lower warm region below the level of about 2,000 feet; 4, absent from Southern Spain, but found in the central or northern provinces; and 5, those not included in the Spanish Flora.

Table III.

Superior region, Sierra Nevada Mountain region of Andalusia Lower region of Southern Spain Central, or Northern Spain, exclusively Absent from Spain

Great Atlas Valleys. 455 sp. 103 82 100 44 126

Superior region of the Great Atlas. 176 sp. 61 19 20 21 55

The figures given in this table are of much interest, proving, as they do, the wide differences that exist between the Floras of two mountain regions not widely separated from each other, and exposed to climatal conditions not altogether dissimilar. We see that three-sevenths of the plants found in the higher region of the Great Atlas are absent from the South of Spain, and that the same remark applies to considerably more than one-third of all the plants found in the portion of the Great Atlas visited by us, although a notable proportion (in both cases) is to be found in Central and Northern Spain. Especially noteworthy is the fact that many of the species thus absent in Southern Spain are plants of Central Europe, most of which extend to the northern part of the Spanish Peninsula, although some of them are altogether wanting in the Floras of Spain and Portugal.

A simple inspection of our list suffices to show that it discloses no trace of affinity between the Great Atlas Flora and that of the Canary Islands, or, to use a term of wider geographical import, that of Macaronesia. The few species belonging exclusively to the latter region and to Marocco are nearly all confined to the coast region.[5] Almost all the species common to the Atlas and to Macaronesia are widely spread Mediterranean plants that ascend from the low country into the valleys. The solitary mountain plant belonging to this category is Arabis albida, the southern form of A. alpina, common in the East, and in the Apennines of Central and Southern Italy, but which, strange to say, has not been found in Spain. In Teneriffe, as in the Atlas, it ascends to about the level of 2,700 metres above the sea. The only fact suggesting a remote affinity between the Great Atlas and Macaronesian Floras is the presence in the former of a species of Monanthes, a generic group hitherto found only in the Canary and Cape de Verde Islands. But the absence of any closer connection clearly shows that the separation between the Macaronesian group and the main land of Africa must date from a period, even geologically speaking, remote.

When we come to sum up the results of the foregoing discussion, bearing always in mind the fact that we possess a mere fragment of the Flora of the Great Atlas, and that future exploration may largely modify our conclusions, we find as its most striking characteristic the presence of a large proportion of plants of Central and Northern Europe, along with a considerable number of peculiar species not hitherto known elsewhere; and we observe that these two constituents, which together form about one-half of the Flora of the region here discussed, amount to very nearly two-thirds of the species found in the higher zone. We remark that of these northern plants none are of Alpine or Arctic type, that nearly all belong to what has been called the Germanic Flora, and all are plants of the plain, not in Europe characteristic of mountain vegetation.[6]

Of the species belonging to the Mediterranean region, which constitute more than one-half of the vegetation of the middle zone, and about one-third of that of the higher zone of the Atlas, the large majority are widely diffused species. The remaining number, for the most part mountain plants, may be divided into three nearly equal sections, some being common both to Southern Spain and Algeria, others to the Atlas and Southern Spain exclusively, and others to the Great Atlas and the Lesser Atlas of Algeria. Nothing indicates any special connection with the Floras of either of those regions.

The absence of any distinct generic types from the Great Atlas Flora has already been remarked. It is not less important to note the absence of any of the southern types, characteristic of the sub-tropical zone, some representatives of which are found in the same or even in higher latitudes, in Arabia, Syria, Persia, and Northern India, and which also appear in the Canary Islands. We finally are led to regard the mountain Flora of Marocco as a southern extension of the European temperate Flora, with little or no admixture of extraneous elements, but so long isolated from the neighbouring regions, that a considerable number of new specific types have here been developed. The physical causes which have operated to bring about these conditions are doubtless numerous and complicated, but the most important of them are easily indicated. The influence of the Atlantic climate, and the prevailing direction of the aërial and oceanic currents, have fitted this region for the habitation of such northern species as do not require a long period of winter repose. In the present condition of the African continent, the Great Desert, extending for a distance of 700 or 800 miles between the Atlas and the river region of tropical Africa, effectually prevents the northward extension of most forms of animal and vegetable life; while in a period geologically recent, it is most probable that the same area was occupied by a wide gulf, which served the same purpose of barring the migration of southern forms.

It may be premature to attempt to trace in further detail the origin of the Great Atlas Flora; but the facts already ascertained certainly authorise some negative inferences. The absence of plants of Arctic type proves that if some mountains of Southern Europe received contributions to their vegetation during the glacial period by means of floating ice-rafts, that mode of diffusion did not extend to the Great Atlas. If we suppose that during the glacial period the temperature of the region north of the Atlas had fallen so low as to permit the migration of northern species across the intervening low country, we find it difficult to understand why so many species which, according to this theory, must have retreated to the Atlas on the subsequent rise of temperature, should have failed also to find a refuge in the mountains of Southern Spain.

It is a further difficulty that if the constituents of the Great Atlas Flora had, to a large extent, travelled by the route here indicated, other species, now inhabiting the mountains of Southern Spain, could scarcely fail to take the same road, and a much nearer connection than is now apparent would have been established between the Floras of these two mountain regions.

It is, at least, possible that the wide diffusion of many of the species constituting the so-called Germanic Flora may date from a period much more remote than is ordinarily supposed; and it is a circumstance not without significance that so many species of this type prove themselves capable of tolerating wide variations in conditions of soil and climate.

FOOTNOTES: