SECT. I 



CRYPTOGAMS 



465 



the shoot the first root develops. The suspensor is situated between the shoot 

 and the foot ; it serves as the first absorbent and nourishing organ of the embryo. 

 Tlie spores of Lycopodium clavatum and other species are sometimes iised in 

 pliarmacy. 



et 



Fig. 411. — Liiropodium noiaplanutunt,. Prothallu.s 

 with antlu'ridia(r<'(), archegonia (ii /■), and a young 

 embryo {k). (After Bruchmann. x 26.) 



Fig. 412. — Development of the embryo in 

 Liicopofliuni comphinatuni. A, Embryo 

 showing the first division.s ; the ba.sal 

 wall I .separate.s the .suspensor (ct) from 

 the body of the embryo ; the transversal 

 walls II and /// (the latter being in the 

 plane of the section) together with the 

 transverse wall IV give rise to two tiers 

 of fom' cells ; the tier next the sus- 

 pensor gives rise to the foot, the ter- 

 minal tier forms the shoob. (X 112.) B, 

 Embryo of medium age ; s, apex of 

 stem ; 6, rudiment of leaf; /, foot, (x 

 112.) C, Embryo .shortly before break- 

 ing out of the prothallus ; hb, the two 

 first leaves covering the apex of the 

 stem; ic, the first root, (x 40.) (After 

 Bruchmann.) 



Order 2. Selaginellaceae (^^^) 



To this order belongs the genus Selacjinella, represented by numerous and for 

 the most part tro})ical species. They have, as a rule, profusely forked, creeping, 

 and sympodially branched stems, but occasionally erect, branched stems ; some 

 form moss-like beds of vegetation ; others, climbing on adjacent plants, possess 

 stems several metres long. In general the Selaginellas are similar in habit to the 

 Lycopodiums. They have small, scale-like leaves which usually exhibit a dorsi- 

 ventral arrangement, such as is shown, for example, in the alpine Selaginella 

 helvetica (Fig. 413), the stem of which bears two rows of small dorsal or upper 



2 H 



