rant} THE MECHANISMS OF FLOWERS. 273 
Every inflorescence bears, besides the proterandrous, androgynous 
flowers, numerous male flowers which mostly develop later, and 
are of obvious service in this marked case of proterandry in 
fertilising the last of the androgynous flowers. 
aibratisie minor, L., is both andromoncecious and androdicecious, 
‘The plant bears as a rule only one umbel, which usually consists 
‘of male flowers surrounded by hermaphrodite flowers ; the weaker 
plants usually bear an umbel consisting only of male flowers. 
ry 
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i 
TFT Jabulgiieigcd 
Fia. 91.—Astrantia major, L. 
__1,—Male flower beginning to expand. One stamen has risen up, but its anther has not yet 
ehisced ; the other four are still bent down within the flower. 
2.—Male flower at the middle of its flowering-period. All five stamens are erect; two anthers 
Bye dehisced and are coated with pollen. 
8.—Hermaphrodite flower “day inci, to expand. Two anthers are erect, but still closed ; the others 
re still bent down within the flower. The styles protrude, but their stigmas are not yet "developed. 
7 Be —Hermaphrodite flower in its second (female) stage. All the stamens have disappeared ; the 
styles have elongated, and their stigmas are mature. 
3 E oe, ovary; s, sepal; p, petal; a, anthers, still bent down within the flower; a’, ditto, erect; 
', ditto, dehisced ; st, stigma, immature; st, ditto, mature. 
_ In regard to the distribution of the sexes, the condition in 
_ Astrantia minor is almost the same as in Veratrum album, with 
_ this exception, that in Astrantia minor no plants occur bearing 
on y hermaphrodite flowers. Veratrum album exhibits the pas- 
sage from proterandrous androgyny through andromonecism to 
androdicecism ; Astrantia minor, with similarly proterandrous herm- 
aphrodite flowers: shows only the passage from andromoneecism 
to androdicecism (609). 
T 
