76 MR. BENTHAM ON LOGANIACE^. 



a valvate aestivation of the corolla is rare, and occurs chiefly among 

 the genera with more than two cells in the ovary, usually classed 

 among Isertiece and Hamelie<s. In Apocynece we have a somewhat 

 similar fruit in Melodinus. In external appearance those of the 

 common species of both genera are described as exactly like 

 oranges, and the strong poisonous properties of Strychnos occur 

 also in several Apocyneous genera; but the aestivation of the 

 corolla forms a decided separation, confirmed by the peculiar 

 foliage, and Strychnos (including JBrehmia) stands more isolated 

 than almost any other Loganiaceous genus. 



The species more or less known, both in the new and the old 

 world, are now numerous. Unfortunately the great similarity of 

 their foliage, the impossibility of preserving their ripe fruits in 

 herbaria, and the difficulty of obtaining even good flowering spe- 

 cimens of large woody climbers, render the discrimination and 

 identification of many of them a difficult task. The arboreous or 

 climbing habit, which has been adopted as one of the first prin- 

 ciples of division, is very difficult to judge of from dried specimens. 

 The presence or absence of the peculiar hooked tendrils of the 

 genus is by no means a safe criterion. They are sometimes so 

 few in some of the most climbing species that herbarium speci- 

 mens are mostly without them, whilst, on the other hand, some 

 of the smaller American kinds are described by all collectors 

 as erect shrubs, although the specimens bear several cirrhi. 

 There is reason indeed to believe, that some species which 

 are erect and bushy in open situations become more or less 

 scandent when growing in moist woods or thickets. A much 

 more marked distinction lies in the shape of the corolla. The 

 tube is sometimes so short as to make it almost rotate, sometimes 

 four or five times the length of the laciniae ; in some species it is 

 slender and equal to the top, in others it is gradually enlarged. 

 The hairs of the laciniae occupy either nearly the whole inner 

 surface, or the base only, or form a ring round the throat or a 

 curved line across the middle of the lobe, or again are wanting 

 altogether. But all these distinctions pass so gradually one into 

 the other, that, however different for instance may be the flowers 

 of S. nucc-vomica from those of S. rubiginosa, no good sectional 

 line can be drawn between them. The number of parts of the 

 flower, quaternary or quinary, is barely of specific value ; it has 

 no relation to habit, and both numbers are occasionally to be 

 found on the same species, although it may often occur in two 

 species otherwise very nearly allied that the one or the other may 



