482 BOTANICAL GAZETTE [june 



EXPLANATION OF PLATES XVI, XVII 



All of the drawings were made with the aid of a camera lucida. Figs. 

 5, 6, 7, 8, II, 13, and 16 represent a magnification of about 30 times. AH the 

 other figures, with the exception of fig. 10, were drawn with a magnification of 

 about 325. Fig. 10 represents a slightly greater magnification. The drawings 

 were reduced one-half in reproduction. 



PLATE XVI 



Fig. 5. — Lamina of primary leaf of sporophyte of Pteris sulcata from both 

 surfaces of which a number of prothallia appear as outgrowths of leaf blade; 

 a, a', antheridia. 



Fig. 6. — Sporophyte of Pteris sulcata with large terminal prothallial portion 

 formed in connection with primary leaf; m, m', and m", young secondary 

 prothallia; 6 and ^, prothallial portions; .y, leaflike outgrowth. 



Fig. 7.— Another sporophyte with large terminal prothallial portion; 

 c, d, e, and /smaller prothallial portions; n, "light" area, cells being neither 

 characteristically sporophyte nor gametophyte. 



Fig. 8. — Sporophyte with well developed petiole of primary leaf; lamina 

 displaced by prothalloid portion ; />, old prothallium; o, antheridium. 



Fig. 9.— Highly magnified portion of gametophytic region (b) and neigh- 

 boring sporophyte cells shown in fig. 2. 



Fig. 10. — Highly magnified portion of n and neighboring cells shown in 

 fig. 3 ; chloroplasts are less numerous and smaller in paler region than in pro- 

 thallial cells; cells of paler region are somewhat intermediate in form, partaking 

 of nature of both generations. 



Fig. II. — ^Leaflike portion; epidermal cells of lamina not typically sporo- 

 phyte, being regular in form and lacking stomata. 



Fig. 12. — Early stage in development of prothallium (p) in connection 

 with petiole of primary leaf. 



PLATE XVII 



Fig. 13. — Sporophyte with prothallium produced from both lamina and 

 petiole of primary leaf; 0, outgrowth from one surface of prothallium. 



Fig. 14. — Highly magnified view of outgrowth (0) shown in fig. 9; cells 

 in outgrowth much smaller than those of prothallium. 



Fig. 15. — Three outgrowths {0 and s) on other surface of prothaUium 

 represented in fig. 9; r, rootUke portion of outgrowth (s). 



Fig. 16.— Primary leaf of sporophyte; b and c, prothallial portions; m, 

 m' , secondary prothallia developed from dorsal surface of b; p, prothalliuiil 

 developed from petiole; a, antheridium. 



