1914] PFEIFFER—THISMIA AMERICANA 135 
Fic. 12.—Longitudinal section of tip of root, with young bud just develop- 
ing; its proximity to the root cap is striking; X52. 
1G. 13.—Older bud, in which the floral axis and secondary root tip have 
begun to differentiate; outlined portion in detail in fig. 19; X 26. 
Fic. 14.—Cross-section of main root with secondary root; X52. 
Fic. 15.—Same main root, showing floral axis in neighboring section; 
Fic. 16.—Later stage, where secondary root has elongated more rapidly 
than floral axis; longitudinal section of main root; X52. 
FIG 17. Cross: section of main root, jongitidinal of floral axis, at base of 
which second secondary root is developing; X 52. 
Fic. 18.—Young flower in longitudinal section, showing arrangement of 
parts; X52. 
Fic. 19.—Detailed drawing (see fig. 13) to show relation of rudiments in 
bud; X27 : 
Fic. 2 —Early stages in development of root and floral axis, as seen in 
habit sania é, same plant as d seen from above; 4. 
Fic. 21.—Subsequent stages; X2. : 
Fic. 22.—Later stage, showing fruit; other floral axes arising on primary 
root and on secondary roo 
Fic. 23.—Cross-section of young flower, showing stamens; X 26. 
Fic. 24.—Cross-section of same flower through ovary; X 26. 
Fic. 25.—Cross-section of style of same flower; : 
IGS. 26, 27, es at megaspore mother cell stage; 835. 
G. 28.—Stamen tube removed from flower, as seen ger side toward 
scaaat big the pollen sacs have dehisced longitudinally; 
Fic pga eet before shedding; the generative cell eae to divide; 
remains a a prothallial cell(?) in one; 835. 
Fic. 30.—Embryo imbedded in endosperm; X 835. 
Fic. 31.—Seeds at maturity; 87. 
