57 



the treatment there given to the genus Lycopodiwm by Pritzel is 

 open to some criticism concerning certain matters, both of fact 

 and of opinion. 



Under Section V. Clavata, there are given two subsections 

 characterized as follows : 



A. Leaves of one sort, shoots externally radial in structure. 



B. Shoots bilateral, often flattened. Leaves in 4—8 rows, of 

 two kinds, the lateral flat, upwardly curved, spreading, broadly 

 emarginate, the upper and lower smaller, linear and appressed. 



The species found in North America which are placed under 

 the former are Lycopodium annotinum, L. alpinum, L. sabinae- 

 folhun, L. Sitchense and L. clavatum. Of these, the first and the 

 last two are undoubtedly to be placed in this category, a state- 

 ment which cannot apply to the other two, namely, L. alpinum 

 and L. sabinaefolium. L. sabinaefolium has been for many years 

 confused with L. Sitchense, but the two differ, among other re- 

 spects, in that the former has a dorsiventrai structure with leaves 

 on the ultimate aerial branches always in four rows, while the 

 ultimate branches of L. Sitchense are of radial structure with 

 leaves in five rows. 



L. alpinum, on the other hand, has a most distinct and easily 

 recognizable bilaterality in its twigs. The leaves of this plant 

 are indeed of three forms ; those of the upper row are " narrowly 

 ovate, acute, those of the lateral rows thick, with one asym- 

 metrically placed nerve, laterally truncate, acute, falcate, curved 

 toward the under side, those of the under side trowel-shaped." * 



In view of these differences, Lycopodium sabinaefolium and L. 

 alpinum should be placed with L. complanatum and L. Chamaecy- 

 parissus, the propriety of which is practically admitted by Pritzel. 

 Speaking of L. Fawcettii and L. Wightianum he says : " The 

 latter plants evidently form a transition to the doubtless nearly 

 related L. alpinum, to which all these species stand closely re- 

 lated." If we place these species in Section B of Pritzel, we 

 should then have a series of North American forms which show 

 as many degrees of divergence from a more primitive type. 



* Lloyd, F. E., and Underwood, L. M. A Review of the Species of Lycopodium 

 in North America. Bull. Torr. Club, 27 : 147-168. 21 Ap. 1900. 



