of the Anatomy of the Genus Selaginella , Spr. 185 
parenchymatous cells round their cortical ends. The peri- 
cycle is one to two layers deep. There is one layer of sieve- 
tubes (absent opposite the marginal protoxylems of the median 
stele), and separated from the xylem by one or two layers of 
parenchyma. 
48. Selaginella Lobbii , Moore. Baker’s Handbook, No. 217. 
The arrangement of the protoxylem-strands and anasto- 
mosis of the steles at the branchings is precisely similar in this 
species to that seen in X. inaequalifolia. There is an epidermis, 
cuticle, feeble hypodermis and thick cortex ending abruptly 
at the lacunae, where there is a slight siliceous deposit. In 
the erect primary shoot there are three chief steles, with 
accessory steles (in thick stems) as in 5 . inaequalifolia. The 
trabeculae consist of simple endodermal cells, but the lacunae 
are more or less filled with green parenchymatous cells, which 
arise in clusters from the inner cortex. The pericycle is, in 
the fully developed stele, about three layers thick. The sieve- 
tubes are in two layers, or occasionally even three layers 
occur, save opposite the protoxylems, where they occur in 
a single layer. In the median stele the sieve-tube layer is 
interrupted opposite the marginal protoxylems. A few 
crushed protophloem-elements are seen beneath the pericycle, 
and one layer of parenchyma separates the sieve-tubes from 
the xylem (PI. XI, Fig. 74). 
In the primary creeping stem a condition of things similar 
to that seen in X. inaequalifolia appears. In the earliest con- 
ditions that I have been able to examine there is a four-rayed 
xylem-mass with four points of insertion of leaf-traces (PI. XI, 
Fig. 66 iv). The protoxylem elements are partially sunk in 
the metaxylem. Possibly earlier conditions still may show 
appearances recalling the central protoxylem of X. spinosa ; 
but I am unable to give further details until I have studied 
the phenomena of germination in the species. The two ven- 
trally placed bands soon separate from the main xylem-mass, 
though they are still united by a common pericycle. The 
dorsal cord then becomes isolated, and the tristelic condition 
of the erect stems is reached. 
o 
