Biological Papers. 295 



Order IX. EQUISETALES : The Horsetails. 

 Family 24. Equisetace^ : Horsetail Family. 



163. Equisetum hyemale L. Common scouring-rush. Banks and 



wet places along streams, E. K.; frequent. (A S U) 



164. Equisetum laevigatum A. Br. Smooth scouring-rush. Along 



rivers and streams, generally throughout the state; com- 

 mon. (A S U) 



Subphylum C. LEPIDOCAULONES : Club-mosses. 



Scaly-stemmed Pteridophytes. 

 Archegoniate plants, in which the stems, which are solid, are closely 

 invested with minute imbricated scale-like leaves, arranged singly. Fibro- 

 vascular bundles remain separate and do not form a closed cylinder. Method 

 of fruiting somewhat similar to that of the Arthrocaulones, by means of 

 sporangia and sporophyls in terminal cones; but the sporangia are single 

 behind each sporophyl, and the cones are slender and lengthened into spikes. 



Class V. LYCOPODINE^: Lycopods. 



Gametophytes small, globular or tuber-like, with rhizoids which barely 

 reach the ground. 



Sporophytes with solid branching stems, more or less prostrate, crowded 

 with small scale-like cauline leaves (whence the name lepidocaulones) ar- 

 ranged in four or more ranks. Sporophores (fertile branches) erect, greatly 

 elongated, often 3 dm. in height; sporophyls and sporanges in four or more 

 ranks, in a lengthened spike or cylinder at the summit. Sporangia one-to- 

 three-celled, solitary in the axils of the sporophyls or on their upper sur- 

 faces. Spores yellowish, minute and all alike (homosporous) in the 

 lycopods proper, or dimorphous (heterosporous) in the selaginellas. 

 These are in separate sporanges, usually in cycles; sometimes with the an- 

 drosporangia in the upper part of the spike and the gynosporangia in the 

 lower part, and again in alternating cycles or otherwise. When homo- 

 sporous the spores give rise to monoecious prothallia; when heterosporous 

 the resulting prothallia are dioecious. 



Order X. SELAGINELLALES: The Ground-firs. 



(Heterosporous E'usporangiate Lepidocaulones.) 



Evergreen archegoniates, producing two kinds of spores: (a) andro- 

 spores, which are minute and roundish-prismoid, and carry minute 

 biciliate sperms, like those of the mosses; and (6) gynospores, 

 which are comparatively large and globose-angular, like a low tri- 

 angular pyramid with a hemispherical base, similar to those of 

 Isoetes, already described. From the gynospores, after fertiliza- 

 tion by antherozoids from the androspores, are developed globular 

 archegonial gametophytes resembling seeds. These plants are on 

 the border line between archegoniate and carpellate; yet they are 

 archegoniates all right, though only a few steps removed from 

 the strobilophytes (cone-bearing plants). 



Family 25. Selaginellace^ : Little Club-moss Family. 



165. Selaginella rupestris Spring. Rock selaginella. Has been 



found nearly all around Kansas; not yet identified here. 



