iqS 



STRUCTURE AND LIFE HISTORIES 



Fig. 143. — Sphagnum acutifoliutn, Ehrb. A, prothallus (pr), with a 

 young leafy branch just developing from it; B, portion of a leafy plant; a, 

 male cones; ch, female branches; C, male branch or cone, enlarged with 

 a portion of the vegetative branch adhering to its base; D, the same, with 

 a portion of the leaves removed so as to disclose the antheridia; E, an- 

 theridium discharging spores; F, a single sperm; G, longitudinal section 

 of a female branch, showing the archegonia (ar); H, longitudinal section 

 through a sporogonium; sg^, the foot; ps, pseudopodium; c, calyptra; sg, 

 sporogonium, with dome of sporogenous tissue; ar, old neck of the arche- 

 gonium; /. Sphagnum squarrosum Pers.; d, operculum; c, remains of calyp- 

 tra; qs, mature pseudopodium; cA, perichaetium. (Cf. Figs. 139 and 142.) 

 (From Schimper.) 



