382 NATURAL UlSTORy OF PLANTS. 



a peripheric parencliyma, are developed the masses of fine cellular 

 tissue, afterwards becoming secondary woody bodies. There is finally 

 the case where, always according to Netto, a stalk of Serjania pro- 

 vided with two peripheric woody bodies, owes this arrangement to the 

 separation in two of a central body divided by two large medullary 

 rays into two woody islets which have been thrown back near the 

 periphery to the state of secondary woody bodies. There are 

 without doubt still many cases to be studied with reference to the 

 arrangement of the tissues in these bindweeds.^ 



The Sapindacece are plants of hot countries, very abundant in the 

 tropical regions of both worlds, rare in temperate countries ; they are 

 only represented in cold countries by the Maples, the Staphylea 

 which are met with in Europe and North America, where also 

 grow ^sculus, Koelreuteria and Xanthoceras inhabiting northern 

 China, and some species of Dodoncea and Alectryon growing in New 

 Zealand. Ten genera are common to both worlds. These are gene- 

 rally the most numerous in species ; for together they number about 

 three hundred and seventy-five, that is to say, half of the total 

 number the whole family contains. The other half, that is to 

 say, nearly four hundred species (described up to the present), 

 divides itself with sufficient exactness into two parts ; the one 

 (about 220 species) peculiar to America, the other (180 species) 

 belonging properly to the old world. This is however much 

 richer in special genera than America, for it counts forty-six, 

 while only eighteen are American. This arises especially from the 

 large number of generic types peculiar, one part to tropical 

 Africa and Madagascar, and the^ other to Australia, and which are 

 without doubt much richer in species than we know of. The Aus- 

 tralian genera, not met with elsewhere, and often remarkable for a 

 distinct organisation, are Akania, Distichostemon^ Diplofflottis, Pseu- 

 datalaya, and Liplopeltis. The continental and insular African types 

 have generally also a particular stamp, as may be remarked in 

 Erythrophysa, Cossignia, Chytranthus, Pseudopteris, Hippohromus, 

 Ptceroxylon, Eriandrostachys^ Macphersonia^ Lecaniodiscus, Crossone- 



^ On the structure of the stems of JEsculm Dieot. 10. — On that of the Maples : C. H. 



see Link, le. Anat. (1837), vii. 6-12. — A. Eich. Sohultz, Nov. Act. Nat. Gur. xviii. Suppl. ii. t. 



mem. ed. 10, 52, fig. 33 ; 62, fig. 36, 37.— 24.— Gratt, Intr. to Bot. 118, 119, 121.— Hen- 



ScHLEiD. Onmtlz. (ed. 1861), 371, fig. 156.— feey, Uc. cjY.— Schacht. Der Baum, 195. — A. 



Henpbet, Micr. Diet. art. Wood. — Oliv. Stem. Juss. ElSm. 49, 62, fig. 



