STRUCTURE. 



55 



and are connate in one plate-like piece in front of the petiole. They are 

 therefore intrapetiolar " (Lubbock, 1894). The insertion is usually a little 

 oblique in Eu-castalia, the curved line of attachment extending farther 

 back on one side of the petiole than on the other. The fused stipular 

 plate persists for some time after the decay of the leaf. It is about 2.5 

 cm. long, more or less, and lies closely appressed to the rhizome ; in 

 general outline it is broadly oval, with emarginate apex. A shallow 

 furrow exists along the line of fusion, into which the petiole fits, and from 

 the ridges on either side of this the tissues taper out to an extremely thin 

 margin. The stipular plate of N. ftava is erect, lanceolate, 2.5 cm. or 

 more in length, thin, rounded at apex, and not persistent. In Brachyceras 

 the stipules are fused at base, with dis- 

 tinct and more or less long-attenuate 

 apices. The other subgenera have dis- 

 tinct, slightly unequal stipules, consist- 

 ing each of a long (2.5 to 4 cm.), narrow 

 (0.3 cm.) wing, adnate to the side of the 

 petiole, with free acuminate apex. In 

 all cases the stipules are whitish or semi- 

 transparent, and soft in texture, and 

 covered on both sides, but especially 

 on the back, with deciduous mucilage- 

 hairs. Interspersed with these on the 

 backs of the stipules in N. odorata and **-"a***x;*Jr.*w^ff.oftwh t . 

 lotus are short fibrous hairs, one to three cells long in the shaft in the former 

 species, much longer, but still few celled, in the latter. Both kinds of hair 

 rest on similar bases of disc-like cells, as will be described shortly. I 

 have observed no vascular supply to the adult stipules of N. lotus, but 

 N. odorata has a principal vein running longitudinally in each ridge of the 

 stipular plate, with about nine smaller ones parallel and nearer the 

 margin. N. flava has also a midrib in each ridge, and may have one 

 parallel vein outside of this. No others have been examined. The 

 cellular structure is very simple. The epidermis of the two sides is 

 continuous around the margins of the stipules, very even on its outer 

 surface, but irregular and angular next to the parenchyma ; it consists 

 of more or less cubical cells in N. odorata and lotus, but in N. flava 

 the cells are wider than deep and longer (in the direction of the length 

 of the stipules) than wide. The interior is filled with nearly uniform, 

 thin-walled cells, roundish or oval, with evident intercellular spaces in 



Fio. 24. Stipules. 



