322 
COM ARUM 
Comarum Linn. = Potentilla Linn. ( C . palustre L. =P. Com.). 
Combretaceae. Dicotyledons (Archichl. Myrtiflorae). 1 6 gen. with 
2 40 sp. trop. and sub-trop. Trees and shrubs with alt. or opp. simple 
leaves and no stipules. Many are climbers, some twining, some with 
hooks formed of the persistent bases of the petioles. Firs, usually 
sessile in racemose infls., g , regular. Typical formula : K 5, C 5, 
A 5 + 5. Ovary inferior, i-loc.; ovules 2 — 5, anatropous, pendulous. 
Style simple. There is a disc on the summit of the ovary, sometimes with 
various outgrowths. Fruit dry, 1 -seeded, often winged at the angles. 
Seed exalbuminous ; cotyledons usually twisted spirally. See Nat . 
PJi. for details. Chief genera: Terminalia, Combretum, Quisqualis. 
Placed in Myrtales by Benth. -Hooker, in Myrtiflorae by Warming. 
Combretum Linn. Combretaceae. 125 sp. trop. and sub-trop., exc. 
Austr. and Polynes. The fruit of C. butyrosum Tal. (trop. Afr.) yields 
a butter-like substance known in Caffraria as Chiquito, and used by 
the natives in place of butter. 
Commelina Linn. Commelinaceae. About 90 sp. trop. C. coelestis 
Willd. is often cultivated. The rhizome of some sp. is edible. The 
chief interest centres in the flr., where there is division of labour 
between the sta. (cf. Heeria). The flr. stands out horizontally and 
the sta. and style project beyond the corolla. The upper 3 sta. 
(in many sp.) are almost sterile, but the lobes are juicy. The two 
lateral lower sta. and the median one are fully fertile, the latter 
bending up so that the anther is opposite the centre of the flr. Bees 
visiting the flr. alight on the lower petals; in so doing they touch the 
stigma, and are dusted by the two lower lateral anthers; they then 
collect pollen from the median anther, and often climb higher up and 
pierce the upper anthers for honey. In some sp. self-fertilisation 
occurs as the style and sta. crumple up in withering. [See Macleod 
in Bot. Jaarb., Gent, II. 1890.] C. benghalensis L. has subterranean 
cleistogamic flrs. (see Nat. Pf.). 
Commelinaceae. Monocotyledons (Farinosae). 25 gen. with 300 sp., 
mostly trop. and sub-trop. Herbs with jointed stems and alt. sheathing 
leaves. Infl. usually a cincinnus of the type seen in Boraginaceae. 
Flr. 5 , usually regular, commonly blue. The typical formula is K 3, 
C3, A 3 + 3, G (3), but some of the sta. are commonly absent or 
staminodial. Calyx and corolla differ in colour and texture. Ovary 
3-loc., with a few orthotropous ovules in each loc. Capsule loculi- 
cidal or indehiscent. Endosperm fleshy ; seed often arillate. Chief 
genera: Commelina, Tradescantia. Placed in Coronarieae by Benth. - 
Hooker, in Enantioblastae by Warming. 
Commersonia Forst. Sterculiaceae. 10 sp. trop. As., Austr. 
Commidendron Burch. Compositae (111). 3 sp. St Helena (p. 148). 
Commiphora Jacq. ( Bcdsamodendron Kunth). Burseraceae. 50 sp. 
trop. As., Afr. C. Myrrha Engl., and other sp., yield myrrh. The 
resin exudes from the tree and collects in lumps. It is used in 
