Fig. 1 8. Embryogeny in the Musci 



A-E, Sphagnum acutifolhim. A, The initial filamentous embryo in longitudinal 

 section. B, Longitudinal walls are being formed. C, D, The young embryo in 

 transverse section, showing the regular pattern of segmentation and the beginning 

 of differentiation. E, Older embryo in l.s. showing the beginning of differentiation 

 in the distal region and the marked enlargement of the foot cells. F, Archesporial 

 region in transverse section (A-D, x 240; E, x 100; after Waldner). G-K, 

 Andieaea. G, A. crassinervia. H, K, A. petrophila. Stages in the embryonic 

 development as seen in l.s. ; in K, the differentiation of tissues is taking place in the 

 distal region. J, Cross-section of a young embryo (G, x 220; H-K, x 165; after 

 Waldner). L-O, Pbascum cuspiilatum. L, M, Stages in the embryonic development 

 as seen in l.s. N, O, Segmentation pattern as seen in transverse section (after 

 Kienitz-Gerloff). P-R, Anhicliiim phascoides. P, R, Embryos in l.s. Q, Embryo in 

 t.s. (L-R after Leitgeb.) S, Tortula miiralis. Longitudinal section of archegonium 

 with young embryo (x 160). T, V, Mniiiin liornum. T, Elongated zygote (x 100). 

 V, Filamentous embryo with a two-sided apical cell (x 160). U, Catharinea undu- 

 lata. Two-celled embryo ( x 100); (S-V, after Bishop). 



