Volume 6 — PLATE CCCXCIX.

COMMELINA TUBEROSA.

Tuberous-rooted Commelina.

CLASS III. ORDER I.

TRIANDRIA MONOGYNIA. Three Chives. One Pointal.

ESSENTIAL GENERIC CHARACTER.

Corolla sex-petala. Nectaria quinque, cruciata, filamentis propriis inserta.

Blossom, six-petalled. Nectaries five, cross-shaped, inserted on their proper filaments.

SPECIFIC CHARACTER.

Commelina, corollis æqualibus, foliis sessilibus ovato-lanceolatis, subtus villosis et inde ciliatis, radice tuberosâ.

Commelina tuberosa. Willd. Sp. Pl. 1. 251.—Dill. Elth. t. 79.

Commelina, with equal flowers, sessile ovate-spear-shaped leaves, villose beneath and thence ciliated, and a tuberous root.

REFERENCE TO THE PLATE.

The herbaceous genus Commelina is a very singular one; and many of its species are remarkable, not so much for the size, as for the structure and brilliancy of their flowers; which, according to the words of the generic character, ought to have six petals: but the present species appears to have but three petals, the three outer being entirely of the nature of a calyx; and effectually answering the purposes of one.

The tuberous-rooted Commelina is a native of Mexico, and in this country requires the treatment of a hot-house herbaceous plant. It is an old, but not common inhabitant of the British gardens; thrives well in rich earth, and is propagated by dividing the tubers of its root, when in a quiescent state; at which period much water is particularly inimical to it.

The genus Commelina can only be distinguished from Tradescantia when the flowers are open; but nevertheless differs very sufficiently, not only in having double the number of stamina, but more especially in the extraordinary cruciform nectaries.

Our drawing was made from very complete specimens communicated to us by the Hon. W. H. Irby, of Farnham Royal, Bucks.