27 8 
CACTACEAE 
thorns present ; flr. rotate) : Opuntia, Nopalea (only 
genera). 
III. PERESKIOIDEAE (habit of ordinary plant, with flat 
leaves and panicles of firs. ; no barbed thorns) : Pereskia 
(only genus). 
[Placed in Ficoidales by Benth.-Hook. ; Cactiflorae by Warming.] 
For further details of this interesting order see genera, and refer 
to p. 167. See also Goebel, Pflanzenbiol. Sch. and Flora , 1895, 
Ganong in Flora 1894, and Bot. Gaz. 1895, Schumann in Nat. PJl. 
and Vochting in Prints. Jahrb. 1894. Euphorbia and Stapelia 
should be carefully compared with the Cactaceae. 
Cactiflorae. The 8th cohort of Choripetalae (Eichler, Warming). 
Cadaba Forsk. Capparidaceae (ill). 14 sp. trop. Afr., As., Austr. 
The disc is prolonged posteriorly into a long tube, and both andro- 
phore and gynophore are present. 
Cadia Forsk. Leguminosae (ill. 1). 4 sp. trop., E. Afr., Madag., 
Arabia. Fir. almost regular with free sta. 
Caesalpinia Linn. Leguminosae (11. 7). 40 sp. trop. and sub-trop. 
Some climb by aid of hooks ( = mid-ribs of leaves). The pods of 
C. Bonducella Fleming are sometimes brought to Eur. by the Gulf 
Stream. Those of C. coriaria Willd. (divi-divi pods) are imported 
from S. Am. and W. Ind. for tanning. 
Caiophora Presl. = Blumenbachia Schrad. 
Cajanus DC. Leguminosae (ill. 10). 1 sp. trop. Afr., As., cultivated m 
warm countries for its seeds, used like peas. It is known as Dhal in 
India, pigeon-pea in W. Ind. 
Cakile Linn. Cruciferae (11. 8). 4 sp. Eur., Medit., N. Am., W. Ind. 
C. maritirna Scop., the sea-rocket, in Brit. It has fleshy leaves 
(p. 186). 
Caladenia R. Br. Orchidaceae (4). 30 sp. Austr., N. Z. The la- 
bellum in some sp. is irritable (cf. Pterostylis, and see Darwin, 
Orchids, p. 90). 
Caladium Vent. Araceae (vi). 10 sp. trop. S. Am., often cultivated 
for their large variegated leaves. 
Calamagrostis Adans. Gramineae (vm). 130 sp. temp., 3 in Brit. 
Calamintha (Tourn.) Lam. Labiatae (vi. n). 40 sp. N. temp., 3 in 
Brit, (basil, calamint). Firs, often gynodioecious. 
Calamus Linn. Palmae (ill). 200 sp. trop. As., Afr., Austr. They 
are mostly leaf-climbers with thin reedy stems. In some sp. there 
are hooks on the back of the mid-rib, but the more common type of 
leaf is one in which the pinnae at the outer end of the leaf are repre- 
sented by stout spines pointing backwards (cf. Desmoncus). The 
leaf shoots almost vertically out of the bud up among the surrounding 
vegetation, and the hooks take hold. The stem often grows to 
immense lengths (500 — 600 ft.); the plants are very troublesome in 
tropical forests because the hooks catch in clothes &c. The stripped 
