37 



either is not dissolved and has become overlapped by a new thicke- 

 ning laj^er of the frond, or, at maturity, only the uppermost part 

 of the roof is fallen away, and the cavity under the remaining 

 part gets overgrown by a new thickening layer or a local new 

 formation; or, as in L. polymorphum and probably also in L. 

 incrustans, by the conceptacles frequently being somewhat im- 

 mersed, and in such cases perhaps always getting overgrown. In 

 species of the section Evanidæ I have also seen the roof of the 

 cystocarpic conceptacles only in part dissolved, but at the same 

 time the cavity effaced by a new thickening layer of the frond 

 and, therefore, the conceptacles not become overgrown, nor a sec- 

 tion of older parts of the frond showing scars after conceptacles 

 filled by local formations of tissue. This, no doubt, corresponds 

 with the above mentioned difference in regard to the thickening 

 meristema of the frond. 



In reference to the character of species I have, besides the 

 general appearance and development of the plant, particularly laid 

 stress upon the shape and size of the conceptacles of sporangia, 

 which, in my opinion, affords a good and in most cases recogni- 

 zable characteristic. But the size of the sporangia themselves is, 

 on the other hand, rather varying, and in shape they are in ge- 

 neral much varying even within one and the same conceptacle. 

 Therefore, they cannot as a rule in this respect serve as an identi- 

 fying character, setting aside their partition. The conceptacles of 

 cystocarps are often uniform in different species, in others again 

 there may be some difference, though in most cases only as to 

 the size. The carpospores are so uniform in the different species 

 examined and, on the other hand, mutually so varying in shape 

 as well as size, that I have in the character of ,species tåken no 

 account of them. The conceptacles of antheridia are, so far as I 

 have seen, always of the same or nearly the same shape as the 

 cystocarpic conceptacles, but probably always smaller. The sper- 

 matia are, I expect, equal in variation to the carpospores, and in 

 this respect the one species nearly resembling the other. Cp. Bo rn. 

 et Thur. Etud. Phyc. p. 99. It should, however, be remarked, 

 that I have not seen or examined any great number of the last 



