iQig] STOUT— INTERSEXES II9 



are fully extended their appearance suggests dehiscence, but an 

 examination at earlier stages of development shows that the 4 

 anther sacs develop as thin plateHke and chiefly indehiscent struc- 

 tures, with only a few scattering thin areas of sporogenous tissue. 



No. 32 (figs. 32, ^T^). — The stamens of this plant protrude 

 only slightly above the throat of the corolla. The general shape 

 of the anthers is maintained, but the anthers are wholly or nearly 

 wholly sterile, and there are only slight irregularities on the sur- 

 face suggestive of any differentiation of anther sacs. 



Nos. 34 and 35. — Numerous plants are to be found having 

 stamens with no trace of sporogenous tissue or even of anther 

 differentiation. When such rudimentary stamens are short, they 

 may be entirely or nearly inclosed within the corolla as previously 

 described for certain plants classed as pistillate (figs. 9, 10). In 

 many cases, however, the stamens are more extended and take 

 on the character of leaves, both as to general shape and color. 

 One of the cases best developed in this direction is illustrated in 

 fig. 34. In fig. 35 the foliose stamens were of nearly uniform 

 width and were much recurved. 



Summary. — It is difficult to arrange or classify the flowers 

 typical of individual plants, such as described, in any fully consist- 

 ent series. Various types of flower and various grades. of develop- 

 ment of stamens are to be recognized, and it is evident that as 

 arranged in descriptions and in plates the flowers of nos. 11-32 

 comprise a series which presents a quite continuous gradation 

 between such extremes as shown in figs, i and 7. Stamens 

 decrease noticeably in length of filaments, in size, in shape, and in 

 dehiscence of anthers, in the relative amount of tissue that is 

 sporogenous, and in the total number and viability of microspores 

 produced. Complete absence of sporogenous tissue is seen in 

 no. 32, almost complete absence of such tissue is seen in no. 30, 

 and indehiscence is complete in no. 28, giving plants that can 

 function only as females. Reduction in size of anthers and of 

 the amount of sporogenous tissue, however, does not necessarily 

 involve also a decrease in size and viability of the spores which 

 are produced, as is shown in no. 18. Marked differences in via- 

 bility of pollen are in evidence. Rarely was any germination 



