Llovd: Two Species of Lycopodium 561 



therefore more readily observable features, for an examination of 

 transverse sections of the branchlets shows that the parenchyma be- 

 neath the lower epidermis is made up in L. chamaccyparissus of elon- 

 gated cells of columnar form with oblique ends, similar but a little 

 broader than those beneath the upper epidermis. This similarity 

 in tissue is carried also into the epidermis, the cells of which, both 

 on the upper and lower sides are nearly of the same size and have 

 lumnia of equal proportions. In L. complanatuui, however, the 

 parenchyma of the lower part of the branchlet is made up of glob- 

 ular cells, while those above arc columnar. Here, too, we find 

 that the cells of the upper epidermis have lumina much more re- 

 duced than do those of the lower. (PI. 370, figs. 9, 10, 11 and 

 12.) The sclerenchyma sheath is also more strongly developed in 



L. chamaccyparissus. 



Furthermore, there is a disparity in the time at which the spores 

 ripen, a fact also not unnoticed by Austin, who records that in 

 Bergen county, New Jersey, the spores of Z. chamaccyparissus ripen 

 "from one to two months earlier than in the type" that is, Z.. 

 complanaUim. Even in Vermont, where such phenomena are 

 compassed in a shorter time, and where these observations were 

 made, there is a difference of at least three weeks to a month in 

 the time of spore-ripening. This fact must be one of considerable 



importance. 



In the light of the above facts it seems strange that these two 

 plants have been regarded by several botanists as not deserving of 

 separate specific rank, though it is interesting to know that the 

 veteran Alexander Braun so regarded them and that Dillenius * 

 fully appreciated their differences, as is evidenced by his excellent 

 ■figures. It appears from descriptions and specimens that the two 

 plants are found abundantly in Europe and have been repeatedly 

 observed growing together. In this connection Luerssent ob- 

 serves : •' The two plants (/. c, L. complanatuui and var. /? 

 chamaccyparissus) in these extreme forms appear so different, that 

 they might well be regarded as distinct species. They pas 

 gradually, however, through intermediate forms, from one to 

 the other." This experience seems, however, not to be dupli- 



*Hist. Muse. pi. 59 (Z. complauatinn) and 60 {L. chamaeryparissus). 174I. 

 I Rabenhorst, Kryptogamen- Flora. Farnpflanzen, i : 825. 



