TILIACEM. 185 



trees ; their liber also, on account of its great development and 

 peculiarities, which render it solid and more or less textile, has often 

 been studied and described. 1 The fascicles which constitute it are 

 undulate and tangential between themselves, to the level of the 

 summit of their most marked curvature, and they are more abundant, 

 as the layers of liber are nearer the interior. 2 The parenchyma is 

 often the seat of abundant mucilaginous deposits, and here, as in a 

 great many Malvacea, we meet with special mucilaginous cells, 

 in which there may be " the procreation of other cells, having 

 their own stratification," 3 and the plasma of mucilage may offer two 

 aspects : " sometimes it spreads itself round the cells, and sepa- 

 rates afterwards into more or less numerous strata ; sometimes it 

 fills the whole cavity, and produces strata separating from the cir- 

 cumference to the centre." The particular cells in the middle of the 

 mucilaginous liquid may in Tilia corallina give birth to nuclei, at 

 first homogeneous, afterwards hollowed into a central cavity. From 

 these facts Trecul has concluded that in the Limes, as in many 

 other Malvo'idece, the mucilage " does not result from a metamor- 

 phosis of the cellular membranes." 



At most about three hundred and fifty species are known, of 

 which two-thirds belong to the Old World. The Brownloiviea series, 

 formed of fourteen or fifteen species, would belong entirely to the 

 tropical regions of the Old World if it did not contain two American 

 Carpodipteras. The Prockiece, on the contrary, are natives of tro- 

 pical America, except Plagiopteron, which can only doubtfully be said 

 to belong to these, and which is Indian. All the species of Elceocarpm 

 belong to the warm regions of the Old World ; and all the Sloaneas 

 were formerly American; but it is necessary to associate with this 

 genus the Asiatic and Oceanic species with imbricated calyx, compos- 

 ing the section Echinocarpus. All the species of Crinodendron were 



1 Upon these questions see Kieser, Mem. (1811), xviii. Suppl., ii. t. 33]. — Schackt, 



upon the Orig. of Pit. (1814), 1. 17. — Mieb., The Lehrbuch, i. 338; Ber Jiaum, 95, 199. — 



Oriff. of Liber and Wood [in Mem. Mus. (1828), Henfe., Micr. Bier., art. Wood. — Oliv., Stem 



xvi. 26, fig.] ; Mem. de Phys. Veg., t. xiv. 19, in Bicot., 8. 



20. H. Mohl., Veb. d. Bait d. For. Gef. des 2 See Rich., Blem., ed. 7, 114, fig. 62. 



Bicot. (in Abh. Akad. Wissench. Munich., i. 3 Tk£cul, in Adansonia, vii. 248. Meten 

 445, fi«\) ; in Bot. Zeit. (1855), 878. — Link., believed the mucilage of the Limes to be con- 

 ic-. Set. (1840), fasc. 2, ii. 7, 12. — C. H. tained in the intercellular channels. 

 Schultz, Bie Cgclose [in Nov. Act. Nat. Car. 



