262 



NATURAL HISTORY OP PLANTS. 



Bursera [Idea) decandra. 



In certain species of Bursera, described under the name of Pro- 

 tium,^ in Asia, and of Icica,^ in tropical America, the leaves are im- 

 paripinnate or reduced to three folioles, usually entire, or even to a 

 single one ; the flowers have four or five parts ; the fruit has an 

 exocarp which is divided more or less distinctly in to panels of stones, 

 and these are united by a slightly resistent columella. In the true 

 Burseras of tropical America (fig. 269-274), the flowers are polyga- 

 mous, 3-5-merous ; the columella of the fruit is of greater con- 

 sistence, the exocarp is detached more distinctly. Usually in three 

 divisions ; the leaves collected towards the summits of the branches 

 have three or a less number of thin and entire folioles. The divisions 

 of the calyx, already deep and more elongated in these species, 



become stUl more so in certain 

 species of Elaphrium^ American 

 plants, glabrous or more often 

 covered with hairs, having pin- 

 nate leaves, often brought together 

 at the summits of the branches, 

 whose folioles, three or more in 

 number, become generally more 

 coriaceous and denticulate; the rachis spreading out slightly in 

 wings in their intervals. Thus constituted,* the genus Bursera 

 contaias forty to fifty species,' arborescent, balsamic, with more or 

 less ramified inflorescence. 



At the side of the Bursera, has been placed, not without some 

 doubt, Crepidospermum, a Peruvian tree, having nearly the same 

 male flower, but with an isostemous, pentamerous androceum, and 

 whose fruit is a compressed drupe, slightly tetragonal, with two or 

 three monospermous stones. The Balsams [Balsamea) are still 

 more certainly closely allied to the Bursera. In these trees and 



Fig. 275. Fniit. 



Fig. 276. Transverse 

 section of Fruit. 



1 BuRM. Fl. Ind. (1768), 88 (not Wight and 

 Akn.). — March, in Adansonia, vii. 213, 260; 

 yiii. 21,62. 



= AuBi. Guian. i. 337, t. 130-135.— J. Gen. 

 370. — Lamk. Diet. iii. 224 ; Suppl. ii. 136 ; III. 

 t. 303.— K. in Ann. So. Nat. ser. 1, ii. 349.— DO. 

 Prodr. U. 77.— Spaoh. Sart. & Buffon, ii. 237. — 

 Endl. (?«. n. 5932. 



3 jAca. Siirp. Amer. i. 105, t. 71. — K. in Ann. 

 So. Nat. ser. 1, ii. 3i7. — 'DG. Prodr. i. 723 

 (part.). — Bndl. Qen. n. 6931. — Maeoh. in 

 Adansonia, viii. 22. 



* Sect. 4: 1. Marignia (Commees.) ; 2. Idea 



(Attbl.) ; 3. Eubursera ; 4. Elaphrium (jAca.). 



5 Sw. Obs. 130.— H. B. K. Nov. Gen. et Spec. 

 Tii. 26, t. 611-613 [Elaphrium).— D^-LS&s. Ic. Sel. 

 ii. t. 55 [Marignia). — Wight et Abn. Prodr. 

 i. 177 (/cics).— Benth. Sulph. t. 7, 8 [Ela- 

 phriiim). — TuL. in Ann. Sc. Nat. s&. 3, vi. 368 

 CElaphrium), 372 [Idea). — Te. et Pl. in Ann. 

 Sc.Nat. s6t. 3, xiv. 297 [Idea), 302. — March, in 

 Adansonia, viii. t. 1, 3 [Protium). — Geiseb. Fl. 

 Brit. W.-Ind. 173.— Waip. Bep. i. 658 [Idea) ; 

 ii. 830 ; v. 419 [Elaphrium) ; Ann. i. 201 ; ii. 

 289 ; iv. 449 [Idea) ; vii. 547. 



