784 _ The Theory of Sex and Sexual Genesis. [August | 
branch. In Ricinus, the castor-oil plant, the flowers are in a 
short panicle, with the female flowers at the terminus of the thick 
main axis, and the much more numerous male flowers borne in 
thick bunches on small lateral branches of the main axis. In — 
some endogens these relative positions are reversed, but only 
where the conditions of nutrition in the parts are also reversed. 
Thus in maize the staminate spikes or tassel form the terminal 
branches of the main stem; but they are far removed: by a long 
and slender portion of the stem from the assimilative organs— 
the leaves—of the plant; while the spike of pistillate flowers that 
forms the ear terminates a short and thick lateral br 
duced in the axil of a large leaf in the middle part of the stalk. 
So likewise where both male and female flowers are borne later- 
ally on a long and tapering spike, as in Stillingia, the staminate 
flowers occupy or form the upper part, and the pistillate the lower 
part of the spike. ; 
In the Composite it is generally the marginal flowers of the 
head that are pistillate, while the thickly-crowded flowers of the 
central part of the head, which are thus less favorably situated as 
regards nutrition, are staminate only, or in some cases > 
The same distribution obtains also in the Umbellifere. Here it 
is often the case that the same umbel or umbellet contains the 
three kinds of flowers, pistillate, perfect and staminate, clearly 
arranged according to the conditions of nutrition. Thus im ae 
cicely (Osmorrhiza longistylus) and parsnip (Pastinaca sativa) m8 
flowers are in compound umbels, and as regards the three see 
just mentioned, have the following arrangement: The cen i 
umbellets of the compound umbel are the smallest of all es 
often bear small staminate flowers only. Umbellets that oa 
neither central nor peripheral, but intermediate in position, ijae 
also intermediate in size, and generally bear small, sun seit 
flowers in their central parts and larger, perfect flowers 7 J 
outer parts. The outer or peripheral umbellets of the Kee : 
umbel are the largest and bear small, staminate flowers outer 
central parts and larger, perfect and pistillate flowers 1m therr i 
parts. Here we have a regular gradation from wholly pae 
wholly female flowers, with increase in the size of all ye ne 
sory parts, which difference in size must result from differen 
the conditions of nutrition, or growth. 
i pio 
While studying the inflorescence of the wild parsmp 
