1851.] Linnean Society. 129 



May 6. 



R. Brown, Esq., President, in the Chair. 



Richard Chandler Alexander, Esq., M.D., was elected a Fellow ; 

 and Dr. Hermann Burmeister, the Chevalier Giovanni Gussone, 

 Prof. J. E. Purkinje, and Prof, Johann Roeper, were elected Foreign 

 Members. 



Read some " Notes on the Leaf of Guarea grandifolia, Dec." By 

 R. C. Alexander, Esq., M.D., F.L.S., as follows:— 



In the enclosed specimens of a Guarea from Jamaica, the G. gran- 

 difolia, Dec, it will be seen that the lower leaflets have fallen off, 

 while younger ones are being developed at the extremity of the 

 same petiole. At the time of flowering, the number of leaflets varies 

 from a single pair to eight or ten pairs ; but as these fall off in the 

 course of a few months, the petiole elongates, and at each successive 

 rainy season, of which there are two in the year, throws out from 

 the end a fresh foliage of several pairs. The lower and older part 

 of the petiole in the meantime remaining attached to the stem, be- 

 comes completely ligneous and round, and acquires a rind distinct 

 from the wood, and covered with lenticelles and a resemblance to 

 pith in the centre; — takes on, in short, the character of a branch, 

 from which it is only to be distinguished by the axillary inflorescence, 

 the absence of buds in the axillae of the leaflets, and the analogy with 

 the closely-allied genus Trichilia, in which the same phaenomenon is 

 seen in leaves deciduous after the second development. In Guarea, 

 at least in this species of it, the leaf seems to be continuous with 

 the branch, without articulation, and to have no definite term of life, 

 hanging on till overtopped and killed by other leaves. Its usual 

 length at that period is from a yard to four and a half feet. 



In Adrien de Jussieu's Memoir on the Meliacea are the following 

 remarks : — 



" The resemblance of the leaflets borne on the same petiole to 

 leaves borne on the same branch becomes more striking still in cer- 

 tain genera, as Guarea, where the extremity of the petiole, after a 

 series of leaflets perfectly developed, presents some which are not 

 yet so, and which appear to belong to another shoot. It would be 

 interesting to ascertain what becomes of them, a thing that I have 

 not been able to do, having had none but dried specimens to 

 examine." 



No. XLVI. — Proceedings of the Linnean Society. 



