6 ROMANCE OF LOW LIFE AMONGST PLANTS. 



Tylostoiiia they are normally four. The Algae, or 

 sea-weeds, are no exception, for in the Floridecs the 

 sexual organs of reproduction are gonidia, four of 

 which are usually formed in a mother-cell, and hence 

 termed " tetragonidia." In some genera of the 

 FiicacecB the protoplasm of the oogonium divides 

 into two, four, or eight. In the Pahnellacece and the 

 Confervoid Algae a quaternary division is so general, 

 both in vegetation and reproduction, that a glance 

 through any volume of analytical plates will furnish 

 a profusion of examples in support of the universality 

 of "number four," and prove it to be the typical 

 number for the Cryptogamia. 



It has been suggested that this quaternary arrange- 

 ment is related to the method of growth by fissura- 

 tion, which prevails in the lower cryptogamia. A 

 simple cell divides in one direction into two, and 

 then in an opposite direction into four ; each of these 

 latter units, in progressive growth, repeats the same 

 process, and so on ad infinitum. This does not seem 

 sufficient to account for the production of four or 

 eight sporidia in a membranous sac, or the four 

 valves in the capsules of Andrcea or the Hepaticcs, 

 but it may have something to do with the division of 

 compound conidia, or sporidia, into two, four, six, 

 or eight cells. If we advert to the moulds, for 

 example, the globose or oval spores (in which the 

 length is scarcely equal to the breadth) are usually 

 continuous, but when the length is equal to, or 

 exceeds the diameter, there is a tendency towards 

 septation, which seems to increase with the length 

 of the spore. The elongated conidium, or spore, 



