ASCLEPIADA CEAE 
251 
but there are a few in temp, regions. In vegetative habit they 
resemble Apocynaceae ; some are perennial herbs, but the most are 
climbing shrubs or lianes, with simple, entire, opposite, exstipulate 
leaves. Latex is present. A large number, especially of the S. Afr. 
sp., are xerophytic ; some, e.g. Periploca, with much reduced leaves, 
others, e.g . Hoya, and still more, Stapelia, with fleshy stems. Epi- 
phytes also occur, of which the most interesting is Dischidia. 
The infl. usually includes many firs, and may be cymose or 
racemose (raceme or umbel). In the former case it is a dichasium, 
but as in Caryophyllaceae the one branch tends to outgrow the other, 
and a monochasial (cincinnus) arrangement may arise in the later 
branchings. When the infl. is axillary, there is usually only one at 
each node; in the axil of the other leaf there is a vegetative shoot, or 
nothing. In some of the genera (see Asclepias) the infl. is extra- 
axillary. The flr. is $, regular, 5-merous, usually small. K5, 
quincuncial, the odd sepal posterior; C(5) usually rotate or cam- 
panulate, with convolute or valvate aestivation. The essential organs 
(5 sta., 2 cpls.) form a complex structure. The sta. and style are 
usually united to form a gynostegium. The cpls. are free below as in 
Apocynaceae, but united at the tip with a common style ; the ovary 
is superior. The head of the style is large and variously shaped, and 
the stigmatic surface is usually upon the edge or under side of it. 
To its margin are united the anthers of the 5 epipetalous sta.; the 
filaments of these are short or non-existent. The pollen in the lower 
group of A. (see below) is united merely in tetrads, in the higher 
group, comprising the bulk of the order, into pollinia, as in Orchi- 
daceae. Usually each anther contains two. In this group also there 
are curtain-like projections at the sides of the anthers, leaving a narrow 
slit between each pair of anthers. 
The pollen is removed from the anthers by a curious mechanism — 
the translator , to borrow the new word introduced by Schumann. 
This differs in the two suborders and so also does the fertilisation 
method. The translator always stands between two anthers and 
serves to carry away half the pollen from each of them. In the 
Periplocoideae it is a spoon- or funnel-like body with a sticky disc at 
the narrow end. Into it is shed the pollen from the two half anthers 
next to it, and as the sticky disc projects outwards in the male stage 
of the flower an insect will be likely to get it attached to its head, 
and carry it about like the pollinia of an orchid. In visiting a second 
flower the pollen may be placed on the stigmatic surface. In the 
Cynanchoideae , on the other hand, there are pollinia, and the trans- 
lator has a different structure. It forms an inverted ^-shaped organ, 
the foot of the Y being formed by the adhesive body (or corpusculum 
as it is sometimes called) ; from this diverge the threads (retinacula) 
which are attached to the pollinia, one in each anther. An insect in 
obtaining honey catches its leg in the slit between the anthers, and in 
