42 



0. atulecita. Spinulis ramuliformibus. T. A. 



I firft difcovered the prefent fuppofed variety in company with my friend 

 Jofeph Woods, junr. in fome dark fliady rills on Finchly Common, and 

 afterwards in a fhady well on Stamford Hill, and in a fimilar well near 

 Yarmouth. It may be at once diftinguilhed by the naked eye from the 

 more common ftate of C. rivularis by its fKll darker color, but under the 

 microfcope it appears to differ only in its numerous fhort fpine-like pre- 

 cedes, of which the joints refemble thofe of the main filament, except that 

 they become gradually narrower, and at length terminate in a fine point. 

 Thefe thorn-like proceffes bear a confiderable refemblance to the ramuli of 

 C. lubrka, Both in the fize, fhape and irregularity of their difpofition, but 

 of their nature I am ftill unable to fatisfy myfelf further than that for 

 *eafons given in my introduction, they are not occafioned by a proliferous 

 germination. The drawing at figure 3 of the fupplementary plate A, was 

 ftiade in 1802, with power I of my microfcope, from the plant which I 

 then gathered near Finchly. With the fketches marked I and 2 (of which 

 the former reprefents the plant when (lightly, and the latter when highly 

 magnified) I have been favored by Mr. Woods, who has fince difcovered 

 this appearance of the fpecies in feveral places about London. It grows 

 not like the foregoing in fprings, but in pools and ditches which are dried 

 up early in the fummer, and ought perhaps to be regarded as a feparate 

 variety. Some of the filaments are entirely fimple, and thefe refemble thofe 

 of C. rivularis ; in others there are a few acuminated proceffes fimilar to 

 thofe above mentioned, whilft others are befet with crowded proceffes of 

 various lengths, and of thefe the longeft are lefs acuminated than the 

 others, and are again fometimes furnifhed with other extremely fhort 

 fecondary fpines. 

 19. bipartita. C. fills fimplicibus, tcnuibus, longiffimis dense compat~Hs, 

 flavo-virentibus ; articulis diametro fub-triplo longioribus, demum bipar- 

 titis. T. 105. 



