342 



LYCOPODIALES 



that the general plan of construction of the prothallus is the same as in 

 the L. cernuum-type, but modified in accordance with the saprophytic 

 method of nutrition. 



FIG. 179. 



A =old prothallus of Lycopodium annotinuui, L. , with young plant projecting beyond 

 the earth-surface (o). Natural size. B= median section through a young prothallus of 

 Lycopodium clavatum, L. X about 30. C = part of this from the middle region of the 

 upper surface, with antheridia in different stages. X 52. Z> = part of the margin of the 

 median section, with meristem and archegonia. X 52. = the epidermis devoid of 

 fungus, with rhizoids ; r = cortical layers, with their cells filled by hyphal coils ; / = the 

 palisade layer, also filled with hypha? ; s^> the storage tissue; ; = the meristem; 

 an antheridia; arch archegonia ; em = an embryo ; f= its foot; zw = its root. (After 

 Bruchmann, from Engler and Prantl.) 



In the third type, exemplified by Z. phlegmaria and other epiphytic 

 species, the prothallus is more attenuated, and repeatedly branched. The 

 delicate colourless branches extend widely through the dead bark on 



