GENERA OF ACANTHACEJ2. 75 



I take the opportunity of adding that I have discovered my Spergu- 

 laria or Lepigonum fallax (Journ. of Botany, viii. 289, 290), to be 

 Arenaria fiaccida of Roxb. Fl. Ind. ii. 447 ; and that the plant appears, 

 from specimens in the Hookerian Herbarium, to be a common weed in 

 India, the Himalaya, etc., as elsewhere. Roxburgh says, " It is only 

 found during the cold season as a weed in gardens about Calcutta, and 

 may have been accidentally introduced from Europe." It seems to 

 have been very frequently called by Indian botanists Spergula pentandra, 

 L., but its constantly three-valved capsule and smooth flower-stalks 

 at once distinguish it. In cc S. pentandra, L., Hooker and Thomson's 

 Herb. Ind. Or.," from Sikkim and Khasia, the capsules are five-valved, 

 and the pedicels glandular-pubescent. On the other hand, the speci- 

 mens from "Him. Bor. Occ. Regio trop." are certainly L. fallax. 



Affi 



L. fallax 

 Diagn. I 



nov. ser. 2, pp. 93, 94, must be the same, correcting his reference to 



" Bourgeau, exs. 1845, n. 410," into either 1849, n. 410, or into 1845, 

 n. 334. 



As Mr. Bentham has kindly pointed out, Medicago calcar, Journ. of 

 Bot. viii. 291, is probably identical with M. Helix, Willd. 



On Professor Nees von Esenbeck's Genera of Acanthace^e, in 

 the eleventh volume of Be Candolle's 'Prodromus;' by George Ben- 

 tham, Esq. 



On the occasion of naming the Acanthacea in the herbarium of the 

 late Dr. Lemann for the University of Cambridge, at the same time 

 that Dr. Hooker was arranging his Indian collections of that order, I 

 have had an opportunity of comparing the specimens named by Profes- 

 sor Nees von Esenbeck in two extensive sets. At the time he was 

 preparing them for the eleventh volume of the c Prodromus/ he had, 

 amongst many others, the whole of the Acanthacea from Sir William 

 Hooker's herbarium, and from my own, and, after completing the work, 

 he returned them with his names attached, and in numberless instances 

 these were the original specimens described. We have therefore had 



large 



points of comparison. 



