EEPEODUCTION OF CRTPTOGAMIA. 



753 



closely resemble the same structures of the Hepaticacese. Ferti- 

 lization takes place in a similar manner to them (see p. 752), 

 and the changes which take place after fertilization in the 

 embryonal cell which ultimately forms a sporangium containing 

 spores {fig. 807) have been already described. (See p. 376.) 



In germination, the spore forms a green, cellular, branched mass 

 or pro- thallus, resembhng a Conferva. This structure is some- 

 times termed protonema (see 



p. 378). Upon the threads Fig. 1102. 



of this structure {fig. 1102), 

 buds (a) are ultimately pro- 

 duced, which grow up into 

 leafy stems (6), upon which 

 archegonia and pistiUidia 

 are afterwards developed. 



4. Lycopodiaceoe or Club- 

 Mosses. — The two reproduc- 

 tive organs of this order are 

 termed oosporangia or oopho- 

 ridia (figs. 795 and 798), 

 which represent the female; 

 and antheridia or poUen-spo- 

 rangia (figs. 796 and 797), 

 which are regarded as male 

 organs. The contents of 

 the pollen-sporangium are 

 called small spores (micro- 

 spores), in which cells en- 

 closing spermatozoids are 

 contained (fig. 1 1 03 c) ; those 

 ofthe oosporangia are termed 

 large spores, macrospores, or megaspores (fig. 798). 



In germination, the macrospore produces a pro-thallus in its 

 interior (fiy. 1104, p), on which archegonia (fig. 1105, a) are 

 subsequently developed. Each archegonium (fig. 1105, a) con- 

 sists of an intercellular canal leading into a sac below, which 

 contains a single germ or embryonal cell. Fertilization is con- 

 sidered to take place by the spermatozoids contained in the 

 microspores (fig. 1103, c), passing down the canal of the arche- 

 gonium and coming into contact with the germ-cell. This cell 

 then grows by cell-division and forms the embryo (fig. 1105, e), 

 which in Selaginella grows down into the pro-thallus (fig. 1105), 

 and ultimately produces a new leafy sporangiferous stem. 



5. Marsileacece or Pepperworts. — The two reproductive organs 

 of this order are generally distinguished as antheridia (figs. 791 

 and 794, a) and pistiUidia sporangia or ovules (figs. 792 and 

 794, b). These two structures are either contained in separate 

 sacs, as in Salvinia (fig. 794); or in the same, as in Marsilea 



3 c 2 



Fig. 1102. Pro-thaUus or protonema of a 

 Moss iFunaria hygrometrica). p. Confer- 

 void protonema; a. Bud; 6. Young leafy 

 stem; r. Kootlets. 



