GENERAL MORPHOLOGY 



301 



But the Fossil Ligulates wer< not all large. There is evidence that 

 small organisms, corresponding in habit to the heterophyllous Selagindlas, 

 existed also in early geological times. The fossil from the Upper Coal 

 Measures, described as Lycopodites Gutbieri, Gopp, can hardly have been 

 anything else. Lycopodites primaevus, Schr., from the Westphalian Middle 

 Coal Measures, though it shows no distinctly Selaginelloid shoot, has 

 heterosporous sporangia, with megaspores more numerous than four in 

 each sporangium, as shown me by Mr. Kidston, in specimens belonging to 

 the Brussels Museum. A similar condition has been described by Zeiller 1 



FIG. 149. 



Plant of Sclaginella spinulosa, with root-system springing from swollen knot at base of 

 the upright hypocotyl. Natural size. 



in a plant from Blanzy, named by him Lycopodites Suissei, where the 

 number of megaspores ^vas found to be 16 to 24. In these cases the 

 reduction in number of the spores as a consequence of heterospory 

 appears to have proceeded less far than in the modern Selagtnella. 

 But, on the other hand, the carboniferous plant described by Bertrand 

 as Miadesmia corresponds in structure, as well as in the heterophyllous 

 arrangement of the leaves and in the presence of a ligule, to Selaginella, 

 while it appears to have progressed towards a seed-like fructification. 

 The minute new species Miadesmia membranacea, Bertrand, has been 

 directly compared with Selaginella spinulosa ( = S. selaginoides, Link) by 

 Miss Benson,- in respect of characters other than the seed-like structure 

 1 Comptes Rcndus, April, 17, 1900. - Proc. Roy. Soc., Series B, vol. Ixxix, p. 473 



