THE CLUB-MOSSES 171 



we may call the micropyle, is left, at the far end 

 of the sporangium. The envelope bears a num- 

 ber of long tentacles, which project beyond the 

 micropyle and may have served to detain the 

 microspores. At the base of the sporangium 

 the sporophyll bears a ligule like that on the 

 vegetative leaf. The sporophyll has a broad 

 blade extending far beyond the sporangium on 



Fig. 19. Miadesmia membranacea. Longitudinal section 

 of "seed"; (tb) vascular strand of sporophyll; (/) blade of 

 sporophyll; (Ig) ligule; (t) tentacles; (c) integument of 

 "seed"; (sm) sporangium-wall; (m) megaspore. From 

 Scott. Studies. X 30. 



either side, so that when the whole was shed 

 the organ was much like a winged seed. 



It has been said above that the Palaeozoic 

 Lycopods attempted to rival the Seed-plants 

 on their own ground. The Selaginetta-like plant 

 Miadesmia is one of the Club-mosses which came 

 nearest to the formation of a true seed. The 

 envelope or integument, and the single megaspore, 



