184 NATURAL HISTORY OF PLANTS. 



ccum inserted quite against the corolla 1 or separated from the inser- 

 tion of the petals by a more or less elevated internode, glandular 

 towards its summit.-— (6 genera.) 



All have common characters, of which the principal ones serve to 

 distinguish the Tiliacea (rather artificially) from the families most 

 nearly related to them, that is to say, Malvacece (comprising the 

 Sterculiea and Bueitncricce) and Dipterocarpacece, Chlenacece, Bivacece, 

 and Ternslrcemiacece. It is certainly too absolute, but it is frequently 

 correct to say that Tiliacece differs from Malvacece? by its stamens, 

 generally free, or scarcely monadelphous or polyadelphous at the base, 4 

 from Malvece, Hibiscea, Bombacece, &c, by its two-celled anthers, and 

 inasmuch as the descending ovules, with ventral raphe, which are 

 often observed in the Tiliacece, are scarcely ever met with among the 

 Malvacece? It is true, almost within the same limit, to say iheBixacece 

 and the Samydece, very similar to the Tiliacece, are separated from them 

 by their parietal placentation. 6 The pignoration of the calyx also suffices 

 almost always to distinguish the Tiliacece from the Dipterocarpacece, 

 where it is generally imbricated, 7 and from the Chlenacece, which are 

 characterized by a sort of disk in the form of a circular enclosure, within 

 which the stamens are inserted, and by the involucre, by which the 

 flowers are surrounded. The Ternstrcemiacece, scarcely separable from 

 the Tiliacece, have also a calyx imbricated 8 at pignoration. Eut we 

 must say that if we were not obliged to have recourse to artificial 

 modes of distinction to render study possible, none of the types could 

 be logically separated into absolutely distinct groups. 



By what is known of the histological organization of the Tiliacece- 

 they approach very nearly the vast group Malvaceae, as we have de- 

 fined it. The structure of the wood of the Limes (Tilia) is one of 

 those which has often been taken as a type among dicotyledonous 



1 Mode of insertion which helongs particu- vacece, the polyadelphous character exists for a 

 larly to the subseries Sloanece. great distance. 



2 Character which only serves imperfectly to 5 But it has generally, especially in the Broion- 

 separate the subseries of Elceocarpece proper lowia series, descending ovules with ventral 

 from the preceding. raphe. (See Bocq., in Adansonia, vii. 63.) 



3 Ktjvih [Malvac, 14) admits in one and the 6 The Tiliacece have very frequently incom- 

 same group with equal title, three large fa- plete cells. (See Adansonia, vi. 238 ; vii. 63 ; 

 milies ; J/nlracece, Hueltneriacect, and TUiacece, x. li)2.) 



and distinguishes these last from the preceding "' Ii is, however, well known that the imbri- 



by their two-celled introrse anthers; a character cation of the calyx is very pronounced in JSchinO' 



evidently much too absolute. carpus, generically inseparable from Sloanea. 

 * In Mollia,A genus nearly allied to the Mai- 8 See Adansonia, x. 34. 



