Plants, and Parthenogenesis. 203 



tion of a single fruitful cell, whilst the numerous embryos pre- 

 sent in an embryo-sac of other Phanerogamia* have each a 

 distinct and independent origin in its fluid. 



If the fertilizing elements of the cellular Cryptogamia are 

 moi"phologically so very unlike those of Phanerogamia, the ana- 

 logy in the construction of the germ in these two great divisions 

 of the vegetable kingdom cannot be extended further ; for it is 

 not known with certainty whether the fertilizing contents of one 

 pollen-cell suffice for the complete development of several germs, 

 nor whether one antherozoid is of equal value with one pollen- 

 grain. And indeed, were this ascertained, the numerous simul- 

 taneous germs of the Mosses cannot be compared with the mul- 

 tipartite embryos of the Gymuospevuije and with the more nume- 

 rous free embryos of the Angiospermse ; for the free central 

 cell of the moss-sporangium would have to be regarded in the 

 first case as a germ-cell, and in the second as an embryo-sac. 



It follows, from our more recent acquaintance with the repro- 

 ductive phenomena of the Linnsean Cryptogamia, first, that the 

 form of the reproductive processes is varied the more in direct 

 p'oportion with the greater simplicity of the organs of vegetation ; 

 and secondly, that the number of germs developed as the result 

 of an act of fertilization is the greater in the simpler-organized 

 plants. 



The validity of this second law will be more thoroughly esta- 

 blished by the consideration of the reproductive processes of the 

 Lichens, on which I have made some remarks above. 



CcENOGONiUM, Ehrenbergf. 



Amended characters : — 



Thallus discoideus in ambitu crescens, contextu stuppeo, e tubulis 

 confervoideis, articulatis, subvirescentibus, strato corticali simplici 

 filanientoso albido cancellatim vestitis intertextus. x\pothecia ter- 

 minalia et lateralia, primitus globosa, clausa, denique suborbiculata, 

 scutelliformia, peltata, stipitata ; hymenio (disco) aurantiaco ; ascis 

 sporigeris, paraphysibus cylindricis apice globosis mixtis ; sporis 

 octonis, ellipsoideis, bicellosis. 



C. Linlii, Ehrenb. 



Tubulorum articuli 0045 mm. longi, 0010 mm. in diam., gelatinam 

 virescentem inchidentes ; apothecia plerumque terminalia, subim- 

 marginata. 



Habitat in Brasilia. 



* I observed from ten to twelve embnos in Hymenocallis, three or foi r 

 in Mmiyifera, Steriphoma, and Socratea : Schacht, indeed, found as many 

 as a hundred in Citrus. 



t Horac Physica; Berolineuses> 1820, p. 120. 



