112 
/. C. Th. Uphof. 
convex on the aligular surface, consequently the ligular surface is 
concave and partly surrounds the stem ; their shape is oblong, 
obtuse, about 0*7 to 1 mm. long (Fig. II, 6). Old parts of the stem 
are leafless, and possess a bright red color. There is a very thick 
cuticle, the cells of the epidermis, hypodermis and outer cortex, 
which are very thick-walled, do not show difference in size (Fig VI, 
1). The inner cells of the cortex are thinner walled, retain their 
protoplasm longer and possess 4 to (sometimes) 6 chloroplasts. I 
was unable to find intercellular spaces, excepting in a few cases in 
very young tissues. With age the space in the thick walled cells 
Fig. V. Selaginella arenicola. J , section of leaf ; 2, attachment of leaves to 
thefstem ; 3, base of leaf and part of stem ; 4, part of epidermis of stem : 5, 
awn at apex of leaf ; 6, longitudinal section of wing of leaf rupincola ; 7, cross 
section of leaf. 
becomes very small, through formation of secondary wall layers ; 
all the walls are impregnated with a red or brown-red pigment, 
which serves as protection against intense sun’s rays. Toward the 
vascular bundle, there is a wide sharply defined lacuna and the 
trabeculae consist of narrow cells, which later sometimes divide into 
two. The spaces in this tissue are large, while they are absent in 
the plants of Group I. The elements of the meta- and protoxylem 
are narrower than in any xerophytic species the writer has worked 
with and stand in close relation with the low water requirements 
and supply of the small leaves. The different parts of the phloem are 
