256 



PLANT MORPHOLOGY 



The archegonium develops as in other pteridophytes, but no basal cell is 

 formed (Fig. 213F-H). It has either one neck canal cell or two of them 

 separated by a vertical wall. 



D H 



Fig. 213. Equisetum telmateia. A, gametophyte with archegonia occurring beneath the 

 upright lobes, X38; B, young antheridium, showing sterile jacket and spermatogenous 

 tissue; C, slightly older antheridium; D, mature antheridium with nearly ripe sperms; E, 

 sperm of Equisetum arvense; F, young archegonium with primary neck cell and central cell; 

 G, slightly older archegonium, showing neck cells, primary neck canal cell, and primary ven- 

 tral cell; H, nearly mature archegonium with neck canal cell, ventral canal cell, and egg; 

 B, C, D, X210; F,'g, H, X325. {A, after Walker; E, after Sharp; B, C, D and F, G, H, after 

 Gilbert M. Smith.) 



Embryo. The embryo does not have a suspensor. The fertihzed egg 

 divides transversely, then into quadrants, the inner segments forming the 

 foot and root, the outer ones the stem and leaf. The stem and root seg- 

 ments soon form an apical cell. 



Summary. The elongated, jointed, longitudinally fluted stem bears 

 numerous small, simple, whorled leaves united to form a sheath around 



