INTRODUCTION TO CRYrTOGAMIC BOTANY. lo3 



slant division of tlieir endochrome, and propagated either by 

 the rupture of the threads, or by active granules formed within 

 their articulations, and escaping by a regular aperture. They 

 vary in the consistency or breadth of the common tube, which 

 is sometimes gelatinous, sometimes membranaceous, sometimes 

 almost cartilaginous ; in the length and constriction of their 

 joints ; in the abundance and depth of tint of their endo- 

 chrome. None of the more typical species seem to form any 

 distinct spores, apart from the zoospores. The branched Con- 

 fervce are very often marine, but by no means exclusively so, 

 and sometimes attain a considerable size. The tufts which 

 they produce vary much in density, as do their filaments in 

 rigidity ; and in one species, which occurs in mountain streams, 

 they are so dense as to present the appearance of solid balls of 

 various size, resembling strongly, in some respects, the hair 

 balls which are formed in the stomachs of some raminating 

 animals. One sj)ecies, 0. mirabilis, Ag., is so large and rigid, 

 as to form a convenient matrix for the development of the 

 spores of one of the red seaweeds, and hence it has been main- 

 tained by the elder Agardh, in accordance with his notions as 

 to the metamorphosis of one species of AJga into another, that 

 a Conferva is capable of assuming a higher degree of organ- 

 ization, and attaining the dignity of one of the Rhodosperms. 

 A minute inspection, however, of specimens soon detects the 

 fallacy, and exhibits the true nature of the phenomenon. It 

 was said above, that the gelatinous element varies very much. 

 This is the case both in the simple and branched species. In 

 the former instance, the effect is only that of making the com- 

 mon mass more slippery ; but where the threads are branched, 

 the increase of this element in quantity and consistence will 

 at length produce fronds, according to the degree of condensa- 

 tion, more or less comparable to those of Nostoc. We have, 

 accordingly, delicate Dvaparnaldiw and Stygeodonia, which 

 hardly hang together, and whose masses are destroyed by any- 

 thing except the most delicate liandling; while in Gluetophora, 

 the jelly is so firm as to form globose or corniform masses, 

 approaching even the firmer Rivularice in consistence. In 

 point of structure, there is no material difference, and the 

 endochrome is frequently resolved into active granules. In 



