SPERMATOPHYTES : ANGIOSPERMS 
359 
elaborate symbiotic relation between flowers and insects, 
through which pollination is secured. In Angiosperms, 
therefore, the wind is abandoned as an agent of pollen 
transfer and insects are used ; and in passing from Gym- 
nosperms to Angiosperms one passes from anemophilous to 
entomophilous ("insect-loving") plants. This does not 
mean that all Angiosperms are entomophilous, for some are 
still wind-pollinated, but that the group is prevailingly ento- 
mophilous. This fact, more than anything else, has re- 
sulted in a vast variety in the structure of flowers, so char- 
acteristic of the group. 
239. The plant body. This of course is a sporophyte, 
the gametophytes being minute and concealed, as in Gym- 
nosperms. The sporophyte represents the greatest possible 
variety in habit, size, and duration, from minute floating 
forms to gigantic trees ; herbs, shrubs, trees ; erect, pros- 
trate, climbing ; aquatic, terrestrial, epiphytic ; from a few 
days to centuries in duration. 
Eoots, stems, and leaves are more elaborate and vari- 
ously organized for work than in other groups, and the 
whole structure represents the high- 
est organization the plant body has 
attained. As in the Gymnosperms, 
the leaf is the most variously used 
organ, showing at least four distinct 
modifications : (1) foliage leaves, (2) 
scales, (3) sporophylls, and (4) floral 
leaves. The first three are present 
in Gymnosperms, and even in Pteri- 
dophytes, but floral leaves are pecul- 
iar to Angiosperms, making the true 
flower, and being associated with en- 
tomophily. 
240. Microsporophylls, The micro- 
sporophyll of Angiosperms is more 
definitely known as a " stamen " than 
A 
FIG. 319. Stamens of hen- 
bane (Hyoscyamus) : A, 
front view, showing fila- 
ment (/) and anther (p); 
J5, back view, showing 
the connective (c) be- 
tween the pollen-sacs. 
After SCHIMPEB. 
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