APPENDIX F.

Comparison of the Maroccan Flora with that of the Mountains of Tropical Africa.

By Joseph Dalton Hooker.

As was to have been anticipated, the Maroccan Flora contains most of the European species which have been collected on the mountains of Abyssinia and of the Bight of Biafra, which alone of the tropical African Alps have been botanically explored. Of these the former have been visited by Schimper and various collectors; whilst the mountains of the pestilential West African coast, of Fernando Po, 9,500 feet, and the Cameroons Mountains, upwards of 13,000 feet, have been ascended for botanical purposes only by Gustav Mann, when employed for the Royal Gardens of Kew.

The results of the latter were published by myself in the ‘Journal of the Linnæan Society of London’ (vol. vii. p. 171), from whence the following observations are for the most part extracted. They included 26 European species, gathered at elevations between 5,000 and 10,000 feet. Most of them are also natives of the Abyssinian Alps, and two-thirds of them are also Maroccan, whilst others will probably yet be found in the latter country.

The following is a catalogue of all the European plants found in the upper regions of the Cameroons Mountains and Fernando Po:—

Height Where found

feet

Cardamine hirsuta 7,000-10,000 Marocco and Abyssinia

Cerastium vulgatum (viscosum Fr.) 8,000 „ „

Radiola Millegrana 7,000 Marocco

Oxalis corniculata 7,000-8,500 Marocco and Abyssinia

Umbilicus pendulinus 7,000-10,000 „ „

Sanicula europæa 4,000-7,500 Abyssinia

Galium rotundifolium 7,000-12,000 Marocco and Abyssinia

Galium Aparine 7,000-10,000 Marocco and Abyssinia

Scabiosa succisa 10,500?

Myosotis stricta 8,000-10,000 Marocco and Abyssinia

Limosella aquatica 9,000-10,000 Abyssinia

Sibthorpia europæa 7,000-7,500 „

Solanum nigrum 7,000-11,000 Marocco and Abyssinia

Rumex obtusifolius 7,000 Abyssinia

Parietaria mauritanica 7,000-8,000 Marocco and Abyssinia

Trichonema Bulbocodium 7,000-9,000 „ „

Juncus capitatus 7,000 Marocco

Luzula campestris 8,000-10,000 Abyssinia

Deschampsia cæspitosa 9,000-12,000 „

Aira caryophyllea 7,000-8,000 Marocco and Abyssinia

Poa nemoralis 7,000-10,000 Abyssinia

Kœleria cristata 8,000-12,000 „

Vulpia bromoides 7,000-10,000 Marocco and Abyssinia

Festuca gigantea 8,500 Marocco

Brachypodium sylvaticum 7,000 Abyssinia

Andropogon distachyus 7,000 Marocco and Abyssinia

The most remarkable features of the Temperate vegetation of these West African tropical mountains are:—

1. Its poverty.

2. The preponderance of Abyssinian genera and species.

3. The considerable proportion of European plants.

4. The paucity of South African genera and species.

5. The great rarity of new genera.

6. The absence of St. Helena and Canarian types.

Upon each of these propositions I have a few general remarks to offer.

In the poverty of their Flora the Cameroons range and Peak of Fernando Po seem to partake of the characteristics of the Abyssinian Alps. We know far too little of the physical geography of either of these districts to hazard many conjectures upon this point, which must to a certain extent be dependent on the arid volcanic nature of the soil and the limited area of the Temperate region. Mr. Mann spent many weeks, and at various seasons, in his explorations, and yet 237 flowering plants were all that rewarded his toil. Geological causes have probably had, in the case of the Cameroons Mountains, much to do with the dearth of species, some parts of the range even now presenting evidence of subterranean heat.

The preponderance of Abyssinian forms is proved by almost all of the genera and half the species being natives of Abyssinia, and by many other species being very closely related to, or obvious representatives of, plants of that country. There are, further, several of the genera and many of the species peculiar to Abyssinia and the peaks of Biafra.

The number of European genera amounts to 43, and species to 26, the greater part of which are British. Very few of them extend into South Africa. The greater part are Abyssinian; the remarkable exceptions being Radiola, Scabiosa succisa, Luzula campestris, and Festuca gigantea, all of which, however, may have been hitherto overlooked in Abyssinia.

I find no other evidence of relationship between the Biafran mountain Flora and that of Marocco than what is afforded by the European species common to both. In most other respects the Floras differ totally, the other mountain plants of Biafra being Abyssinian or Cape types, or more nearly related to tropical African ones.