THE PECTINATE ORGANS OF THE WATER-CHESTNUT. 85 



by Roxburgh, who has well figured and described them (Roxb. PI. 

 Cor., t. 234), but there are real stipules also present with the young 

 leaves." 7 



In the Flora of British India, alluded to by Trimen, I find these 

 lines : " Leaves (of the genus Trapa) dimorphic ; submerged opposite 

 root-like, pinnatipartite, with filiform segments." 8 Duthie gives the 

 following characteristic of the genus : " Stem long, flexuose, ascending 

 in the water, the more submerged portions giving off at intervals pairs 

 of green pectinate spreading organs from below the margins of the 

 scars of fallen leaves. Leaves alternate, approximate in the form of 

 rosettes" 9 . Loudon speaks of Trapa natans as of a" curious aquatic 

 with long brown and green roots and floating leaves, with petioles 

 inflated into a tumour as in the marine algoe." 10 According to 

 Cooke those " pectinate organs " are termed " adventitious floating- 

 roots " by Barneoud. 11 De Candolle gives this description of the 

 genus Trapa : " Herbce aquis innatantes. Radices fibrosa?, folia 

 infima opposita, cetera alterna, inferiora pinnatipartita, capillacea, 

 fere tit in Myriophyllis, summa in rosulam conferta." 1 " Cooke, too, 

 calls those submerged organs pinnatipartite, 13 and adds in a note, 

 that " considerable diversity of opinion exists as to the exact function 

 of the pectinate organs." 14 



From the foregoing we may collect that there exist different opinions 

 not only with respect to the morphology but also the function of the 

 pectinate organs. They are considered by some to be stipules, by 

 others true leaves, and, again, by several even roots. As regards their 

 outer morphology they are described as being pectinate, pinnatipartite, 

 pinnatisected, radiciform, capillary, ramous, as resembling the leaves 

 of the Myriophylla. 



In the following I shall give the external and internal morphology 

 of the " pectinate organs" of Trapa bispinosa, and by drawing the con- 

 clusions from the given data, I shall try to arrive at a satisfactory 

 explanation of those interesting organs. 



7 Trimen, 1. c., p. 236. 



8 Hooker, Flora of British India, Vol. II., p. 590. 



T. F. Duthie, Flora of the Upper Gametic Plain, p. 357. 



10 Loudon, Eucycloptcdia of Plants, p. 104. 



11 Mem, l.i Trapa natans, Ann. Sci. Nat. sc'r. 3, v. P. [1S-18] p. 222. 

 }£ De CandoPe, ProJromus Stfat. Nat, Regni Vcgclabilis, III., p. 63, 

 13 Cooke, 1. c, p. 515. 



** Cooke, 1. c, p. 518. 



