SCITAMINEJ:.. 323 



Tamus (Bryony) has a berry, Dioscorea (Yam) a thin-walled, 

 3-edged or 3- winged capsule (Fig. 313). Both have subterranean 

 or aerial tubers ; the Yam very often also developes tubers in the 

 axils of the foliage-leaves ; tuberous roots are said to occur in 

 D. batatas. The tubers of many species of Yams (D. batatas from 

 China and Japan, D. alata, South Sea Islands and India, D. 

 bulbifera) are a very important source of food in the Tropics, 

 especially the first-named. Testudinaria ; Rajania. The tuberous 

 stein of Tamus communis and Testudinaria elephantipes, and some species of 

 Dioscorea is formed from one single internode (epicotyl), and the aerial shoots 

 are developed from adventitious buds ; in T. elephantipes the stem is aerial, and 

 covered with thick scales of cork, regularly arranged, and separated by grooves. 

 Tropical order (167 species) ; 2 species (Tamns communis and Bordered 

 pyrenaica) in Europe. 



Family 6. Scitamineae. 



The flowers belong to the ordinary monocotyledonous type. 

 They are hermaphrodite, epigynous, and have either a petaloid 

 perianth, or calyx and corolla ; they are, however, zygomorphic 

 or unsymmetrical, and of the stamens most frequently only one 

 is completely developed, the others being generally represented by 

 petaloid staminodes. The ovary has 3 loculi, more rarely it is 

 unilocular with the suppression of 2 loculi. Endosperm is 

 absent (except Zingiberacece) ; but, on the other hand, there is a 

 large perispenn. To this family belong large, glabrous, especially 

 perennial herbs with rhizomes ; leaves large, distinctly divided 

 into sheath, stalk, and blade, the latter being moi-e or less 

 elliptical or lanceolate, entire, with pinnate venation, and always 

 with a very well-pronounced midrib, gradually tapering towards 

 the apex, and giving off numerous branches, which run outwards, 

 towards the margin, at a lai'ger or smaller angle ; these lateral 

 veins are closely packed, and parallel, but with only weak, con- 

 necting branches between them ; the leaves, therefore, are easily 

 torn pinnately (Figs. 314, 317). The leaf-sheaths close tightly 

 round each other and form a false stem. 



This very natural family comprises orders closely connected 

 with each other, but is not itself nearly allied to any other family. 

 First in the series stands : 



Order 1. Musacese. The petaloid perianth is strongly 

 zygomorphic, the anterior leaf being very large (a kind of 

 " labellum "), the posterior one small ; only the posterior stamen 

 is wanting, or is rudimentary, the other five are developed, and 



