1892]. On the Stem and Sporangium of Botrychium. 217 
in the so-called spindle stage of division, with probably forty to 
fifty cells in the sporangium. Another stage (fig. 8) showed 
Se RTLANATION oF Plate XVI.—Fig. 1. Young stem of Botrychium Virginianum 
apical I cell dividing; four segments shown. X 225.—Fig. 2. Pinnule; 
longit 
growth; outlines of three segments shaded. X 225.—Fig. 3. Portion of 
udinal section of pinnule showing origin of sporangium (large cell) X 450. 
i i i segments ha been 
eal. 
cut > iy Seen ha after apical cell is formed, tw Ss gy of 
bald —Fi i rowth, two 
the six arches porangium in an advanced state 
f, ta z . 6. BS 
nicer layer. X 170,—Figs. 7 and 8. Archesporium cells dividing, 
g 
wo layers of cells surrounding them. X 325 
‘Bower: Is th . " Rees 
type in the € eusporangiate or the leptosporangiate the more primitiv 
ty the ferns? Annals of Botany, vol. V. no. XVII. 
ol. XVIT.—No, 7 
