Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/158

138 Stemonitaceœ, with typically separate sporangia, has a singular exception in the curious confluent condition of S. fusca (Mon. 110). In the genus Chondrioderma the position of C. Michelii arrests one's attention. The examination of some thousands of C. testaceum in the field suggests that C. reticulatum and C. niveum are the natural offsets of the former. At least these three have an interesting habit of commensalism suggesting community of descent, whilst C. Michelii is conspicuous by its absence. One learns, however,

from Mr. Lister that American observers have "sent fine specimens of flat winding plasmodiocarps corresponding with Rostafinski's type of C. reticulatum, which Mr. Wingate (of Philadelphia) has found in company with the stalked C. Michelii." Here we might suggest that C. testaceum may be taken as a convenient centre from which the other forms diverge.

It is certainly agreeable to some of the workers in this field that many of the varieties named and described in the monograph have been omitted from the Guide. This course simplifies the subject considerably, without diminishing the practical value of the classification. Probably the most interesting portion to the ordinary