38 NYMPHAEACEAE [CH. 



destroyed, formed a hollow for the lighted tobacco, and the 

 smoke passed through the 

 air-spaces in the stalk 1 . 



The mucilage which coats 

 the young organs in most 

 of the Nymphaeaceae will 

 be considered later 2 . It is 

 secreted by glandular hairs 

 (Fig. 20). 



Oiir ~Rrif-ic;h Waterlilips FlG ' 2O ' Brasenia Schreberi, J. F. Gmel. Part 



sn wate ines of transverse section of yojmg leaf to show 



belong tO the Central tribe thesecretoryhairs,w. h. .surrounded by alayer 

 r r .-, XT , . of clear mucilage, m. [Goebel, K. (1891-93).] 



of the family Nymphaeoi- 



deae of which Euryale and Victoria also form part. Two 

 other tribes are recognised the Cabomboideae and the Nelum- 

 bonoideae which differ markedly from the Nymphaeoideae. 

 The Cabomboideae are in many respects relatively simple ; they 

 have free carpels, and Cabomba also has a less complex type of 

 anatomy than the rest of the family. Brasenia Schreberi, which 

 belongs to this tribe, is notable for the enormous development 

 of surface mucilage (Fig. 20) 2 . 



The Nelumbonoideae include the Sacred Lotus, Nelumbo 

 Nelumbo and one other living species belonging to the same 

 genus. In Cretaceous and Tertiary times the genus had, how- 

 ever, a cosmopolitan range (Fig. 2 1) 3 . This tribe, and the Water- 

 lilies proper, differ so much that they have been described as 

 having nothing in common except the number of cotyledons, 

 the polypetalous flowers, the numerous stamens, and the medium 

 in which they live 4 . The acyclic arrangement of the petals and 

 stamens might also be mentioned as constituting a similarity 

 to some of the Nymphaeoideae. The exalbuminous seeds 5 and 

 the carpels sunk in the curious obconical receptacle, are indeed 

 difficult to reconcile with the characters of the other Water- 

 lilies. Gwynne-Vaughan 6 pointed out that Nelumbo shows an 



1 Raffeneau-Delile, A. (1841). 2 See pp. 271, 272. 



3 Berry, E. W. (1917). 4 Trecul, A. (1854). 



6 Wettstein, R. von (1888). 6 Gwynne-Vaughan, D. T. (1897). 



