84 



THE "PECTINATE ORGANS" OP TRAP A BISPINOSA, 

 ROXB. ( WATER-CHESTNUT ). 



By 



E. Blatter, s.j. 



( With a Plate.) 



(Bead before the Bombay Natural History Society on 26tli January, 190G.) 



Cooke in his excellent " Flora of the Bombay Presidency," when de- 

 scribing Trapa bispinosa speaks of " numerous opposite pairs of root- 

 like spreading pectinate organs," and adds immediately "(?floating 

 roots ")i. 



" I think it is well known that the uppermost leaves with their 

 rhomboidal blades lie on the surface of the water and are grouped 

 into rosettes. There are, besides, for each leaf a pair of scaly, deeply 

 divided stipules 2 , and just from below these stipules arise those ' pecti- 

 nate organs,' which have caused so great a variety of opinion." 



In the " Genera plantarum " the genus Trapa is described as follows : — 

 " Herbce nat antes, Folia 2-formia, submersa opposita, pinnatisecta, 

 radiciformia ; emersa rosidata, petiolata, rhombea, dentata, petiola infiaia 

 spongiosa." 3 Baillon writes to the same effect: "The slender floating- 

 stems bear two kinds of leaves. The lower, submerged, are opposite, 

 pinnatisect, not unlike finely pectinate roots." 4 W. Roxburgh 

 gives the following description : — " Stipules two pairs, the superior are 

 simple, semi-lanceolate, and caducous, the inferior pair at first simple 

 and filiform, but becoming ramous by age, permanent." 5 The same 

 opinion as regards Trapa bispinosa is expressed by Trimen in the fol- 

 lowing : — " The more submerged part of the stem," he says. " is thick- 

 ly set with pair of green pectinate spreading organs ( ? roots ) coming 

 off from immediately below the position of stipules of fallen leaves, and 

 1 — i^ i n . long." 6 Later on he continues : "The pectinate submerged 

 organs cannot be considered as leaves (as in Flora British India, following- 

 Wight) ; their position suggests a stipular nature, and they are so called 



1 Cooke," Flora of the Bombay Presidency," Vol. I., p. 518. 



2 There haa crept in a .mistake in Cooke's Flora (p. 515) where the author describes 

 the order Onagracem as extipulate, though, later on, he speaks t f the stipules o! Trapa bis- 

 'pin os a. 



3 Benthim et Hooker, Genera plantarum, Vol. I., p. 793. 

 * Baillon, Natural History of Plants, Vol. VI., p. 477, 



1 W. Roxburgh, Flora Indica, p. 144, 



6 Trimsn, Flora, of Ceylon, Vol. II., p. 235. 



