380 NAl URAL HISTORY OF PLANTS. 



differential traits, striking in the extreme types where we could not 

 faU to appreciate them, diminish, insensibly in numerous intermediate 

 types and sometimes by an uninterrupted series of gradations, the 

 observation of which will lead to the conclusion that there is only the 

 most artificial line of demarcation between the tribes with regular and 

 those with irregular flowers formerly, separated by Bltjme j between 

 the series of A and B distinguished for the same reason by J. D. Hookee 

 in the group of Sapindece ; between those of the Soapworts and the 

 Pancovias, which, following his example, we have preserved, as more 

 convenient in practice, when it is a question of a family of which we 

 have so much yet to learn. But it will not be impossible to improve 

 on this in future as regards the natural characters. We do not think, 

 for example, that Diploglottis ought to be relegated to a different 

 series from Cupania to which it is attached by so many common 

 characters, simply because its flower is irregular. We see the closest 

 affinities between HarpulUa and Cossignia, the first being regular, the 

 latter irregular. We do not affirm that the Hemigyrosas of Bltjme, with 

 their irregular flowers, are not however quite as closely allied to the 

 irregular types Anomosanthes and Scorodendron, from which J. Hooker 

 was bound to separate them, as to Pancovia near which he was 

 obliged to place them. A genus such as Dittelasma, separated con- 

 siderably from Sapindus on account of its irregular floral type, has 

 however such affinities with it that it was for a long time considered as 

 congeneric. These are, it is plain, all questions which stUl require 

 to be thoroughly examined into. 



As to the organs of vegetation, the Sapindacece are very rarely herbs, 

 sufirutescent at their base ; and in that case they are climbers holding 

 on by tendrils, as occurs so frequently when they become enormous 

 woody bindweeds often described in standard works on account 

 of their abnormal structure.^ In Paullinia, Serjania^ and Urvillea, 

 for example, these stems are often characterised by the presence of a 

 central woody body surrounding a pith and a medullary sheath, but 

 itself surrounded , and sometimes with great regularity by three or more 



1 Gaudich. Seen. Sur I' Org. Ve'get... (1841), 1861), 343, t. 161, 162.— Ceueo. in Bot. Zeii. 



t. 13, 18 ; in Guillem. Jrch. £ot. a. 501, t 19. (1851), 481. — Schacht. Lerbmh, n. 67. — 



— A. EiCH. JBZ^. ^d. 10, 77, fig. 45.— Mart. Metten, in Zimiaa (1847) 582. — A. Juss. 



Oelehrt. Anzeig. (1842), 390. — Teevir. in Bot. Monogr. Malpigh. (1843), p. i. 110. Oliv. Stem 



Zeit. (1847), 393. — Schleid. Orundx. (ed. Dicot, 10. 



