XIII 



LYCOPODINEAl 



S27 



cells show more or less marked cutinisation. The number of 

 protoxylems in most species is two, but there may be accessory 

 ones. 



The cortex is composed in most species of delicate paren- 

 chyma, with few or no intercellular spaces, and most of the 

 cells contain chlorophyll. In species like S. lepidophylla, which 

 grow in dry localities, the cortical cells are sclerenchymatous, 

 with deeply-pitted walls and no lacunae are present in the stem. 

 In the creeping stems, even in polystelic species, there is but a 

 single stele, which gradually passes over into the separate steles 

 of the upright stems. 



Fig. 305. — A, Rhizophore, with roots of 5". Kraussiana, Xi^A; B, cross-section of the 

 vascular bundle of a root, X430; C, median longitudinal section of the leaf, X215. 



The Leaf (Gibson {4, 5); Hieronymiis (i)) 



• 



The leaves of Selagmella are always of simple structure, 

 much like those of Lyco podium. Gibson (4, 5) has made an 

 exhaustive study of their structure, and the following account 

 is based upon his studies. 



The leaf may be perfectly symmetrical in outline, or may 

 have one side more developed than the other. In some species 

 there are characteristic basal appendages, or auricles. 



A section of the leaf (see also Fig. 303) In most species 

 shows a definite upper and lower epidermis, which may be com- 



