132 THE JOURNAL OF BOTANY 
is fitted to the conformation of some particular insect. he 
wondrous. variations seen in the forms of the cuculli are probably 
means to the same end. 
The pollinium is frequently left only partially engaged in the 
slit, and how it is propelled into the deep, recessed portion of the 
stigmatic chamber is not clear. The edges of the slit are in some 
walls. The valves are frequently horny in eres and, if _ 
apart and eutler _ g together again. Where, as in som 
alve 
instances, the yv are set with i inwardly- AG anid teeth, the 
spring-like compression aged ep and ange the slippery pollinium 
inwards, but in many ¢ o teeth exist. In some eases the 
margins of chs slit are ot like, eciina, ee iy and here a 
variation in turgidity ~ act as the propelling fore 
On 
may examine many flowers before fin bane a trapped 
pollinium. Flowers iin which the akcergs have been carried 
off ore commonly seen. There must needs be adaptation 
between the pollinium and the slit it is Geatinol to occu 
narrow slit calls for a flattened pollinium. Where the valves are 
in close contact throughout, with no definite orifice at the angle, 
and no divergence be _ the extremely flattened pollinium, as 
seen in the fly-wing type, may be confidently looked for. Some 
and there may be elastic recoil when it is displaced from its 
setting. The corpusculum, especially if large, may be a leading 
factor in drawing the pollinia together; or the retinacula may 
the active agents. ain, the pollinia themselves may swing 
plied Ape retinacular extremities, into which they are sometimes 
a cup. Doubtless in ny cases all three elements of 
the ‘ttahialatoF take part in varying degree. In the large-flowered 
species, details = terres are readily made out with the 
hand-lens; in the small-flowered species a magnification of fifty 
diameters Beoditiek. necess vite 
ASCLEPIAS FALLAX Schlechter. No. 1352. Erect habit. Flowers 
erect. Cuculli aa ivory-white in colour; they give the character 
to the flower. dour disagreeable and suggestive of valerian. 
Translator vaahanaioe orpusculum moderately large. Retina- 
cula short, stout, and thickened at either extremity. Acre of 
fly-wing type. Stigmatic slits very narrow. Angle sa 
A. LINEOLATA Schlechter. No. 1353. Tra ae Corpus- 
culum large. Retinacula short and stout. Pollinia of fly-wing 
type, one side having a concave outline. Proximal end of pollinium 
enclosed in a socket-like dilatation of retinaculum. Stigmatie 
valves horny; slit narrow, sides recoiling elastically after being 
ngle salient; in profile see ee of the valves re- 
sembles that of the ram of a man-of-w 
