REMARKS ON BOTANICAL BIBLIOGRAPHY. 167 



well as by the dioecious character, which separates it from N.jiexilis. 

 Apparently common in many parts of Europe, and occurring in 

 Asia, North Africa, and North America. It is our most frequent 



British Xitella. 



Ponds, pools, ditches, streams, &c. May and June. Corn- 

 wall, W. ; Devon, S. ; Wight; Hants, S. ; Sussex, W. and E. ; 

 Surrey; Essex, N. ; Oxford; Norfolk E.; Cambridge; North- 

 ampton; Salop; Lanes., S; York, M.W.; Durham; Cumberland; 

 Fife; Forfar; Aberdeen, S. ; Kerry, N. ; Cork, N. ; Dublin; 

 Gahvay, W. ; Leitrim ; Donegal ; Antrim. 



[We have not been able satisfactorily to refer any British plant 

 to either of the following species, as it is necessary to examine 

 fresh specimens, but probably both occur : — 



N. syncarpa, Chevallier Lutet. Flor. Gen., ed.ii., vol. ii. (1836), 

 p. 125; Fviitz. Tab. Phyc, vii., t. 81, f. 2; Braun, B. & S. Exs. 

 76 ; Nordst. & Wahlst. Exs. 1, 2. — Chara syncarpa. Thuill. Flor. 

 Par. (1799), p. 473 ; Eeichenb. Icon. Bot., f. 1073-5. This differs 

 from N. opaca by its very slender habit and simple branchlets in 

 the female plant, by the globules and nucules being covered with a 

 mucilaginous coating, and by the nucules being faintly striate. 



N. capitata, Ag. Syst. Alg. (1824), p. 125; Braun, B. & S. 

 Exs. 26-28, 104; Nordst. & Wahlst., 3, 4. — Chara capiUari*, 

 Krocker, Flor. Siles., vol. iii. (1809), p. 62. — C. capitata, Nees, 

 Benkschr. der K. Baier. bot. Ges. 1818, p. 80, t. 6. — C. elastica, 

 Auiici, Descriz. di alcune sp. nuove di Chara (1827), p. 9, t. 1, 

 f . 2 and 3. Female branchlets divided into 2-3 rays. Nucules 

 with sharp, prominent spiral cells and, as well as the globules, 

 with a mucilaginous coating. Braun has referred specimens in 

 Herb. Kew, from Llyn Idwal (W. Wilson), Killamey (Harvey), 

 and Kent ' Stowting ' to this species.] 



BEMABKS ON BOTANICAL B1BLIOGBAPHY. 



By B. Daydon Jackson, Sec.L.S. 



Having been engaged for more than two years in preparing a 

 kuide to the Literature of Botany (now almost completed) for the 

 Index Society, certain defects in the present bibliographical 

 authorities have been forced upon mv notice, and I beg to offer 

 some suggestions for the guidance of those who may hereafter 

 undertake the publication of any work on that subject. Previous 

 {J .engaging in the compilation I have mentioned, I had found 

 ttitzel's ' Thesaurus Literature Botanicse ' equal to my occasional 

 jvants, but constant use for a long time of both editions has 

 familiarised me with the merits and defects of that work, probably 

 ! n a greater degree than the majority of botanists. I will therefore 

 ni(lul w i n a f ew remai .i iS on the ' Thesaurus' itself, before setting 

 torth my own views upon future bibliography. 



