the Anatomy of the Genus Selaginella , Spr. 135 
12. S. serpens, Spr. (Figs. 4, 14, 29.) 
Ventral leaf. Ovoid, blunt, with sclerotic spiny margins (Figs. 4, 14). 
The cells of the ligular epidermis are polygonal or rounded, becoming 
elongated with sinuous lateral walls on the basal lobes. The elongated 
cells of the aligular surface are provided with one row of warts ; the 
cells become shorter near and over the midrib. Stomata occur on 
this side only. 
Dorsal leaf. The leaves are ovoid, cuspidate, very oblique, and 
the margin is more sclerotic than in the ventral leaf. Stomata occur 
on both sides — on the aligular side, where they are frequently sclerotic, 
over the midrib ; and on the ligular side on the outside lobe. The 
elongated cells of the ligular epidermis have 3-4 rows of warts. 
Section. As in the type, but the mesophy 11- cells are short and 
closely packed (Fig. 29). 
13. S. cuspidata, Lk. 
Ventral leaf The leaves are broadly ovate, and cuspidate with 
a broad marginal band of sclerotic fibres, trichomatous especially 
towards the base. These marginal cells have no chloroplastjds. 
Stomata occur on the ligular face occasionally, especially on the 
margins of the basal lobes. The aligular epidermal cells are elongated 
but not wavy ; there are numerous stomata. 
Dorsal leaf. The leaves are almost as large as those of the ventral 
side, and similar in form and margin. Stomata occur on the lamina, 
but not over the midrib, of the ligular face. Numerous stomata occur 
on the aligular face. 
Section. As in the type, 
14. S. helvetica, Lk, (Fig. 23.) 
Ventral leaf. Reaves awhshaped, bluntly pointed, unequal-sided, 
and faintly spiny. The epidermis of the ligular face, which bears no 
stomata, consists of polygonal cells over most of the surface, but of 
elongated cells over the basal and apical regions. 
Dorsal leaf. The dorsal leaves are nearly as large as the ventral, 
and of similar shape and histological characters. Stomata occur near 
and over the midrib on the aligular face, and sparingly also at the edge 
near the base. On the ligular face stomata also occur over the middle 
and edge. Their walls are often sclerotic. 
Section. The mesophyll consist of rows of elongated cells, which 
curve upwards from the ventral to the dorsal surface (Fig. 23). 
