614 



being the largest and most vigorous, is that which, in ordinary circum- 

 stances, develops itself into a branch ; but the one below it does cer- 

 tainly vegetate, and is visibly protruded from the cavity, so as to 

 indicate a capability of immediately replacing the upper one, if that 

 should be destroyed by frost or other accident. I wish some of your 

 correspondents would examine other species, and also the Platanus. 

 Professor Nuttall informs me that this mode of producing buds occurs 

 in Psidium. May it not be a general property of tropical trees which 

 do not form visible external winter-buds ? — Id. 



307. On the buds of Conifer<B. Unlike dicotyledonous trees, which 

 invariably produce a bud at the base of every leaf, either axillary or 

 intra-petiolar, the Coniferae have the greater part of their leaves des- 

 titute of buds, which are comparatively few, and scattered at distant 

 intervals along the branches. On the axis of trees of this order, the 

 branches exhibit a tendency to develope themselves in a peculiar 

 manner, so that the tribe is characterised by the pyramidal or conical 

 shape of the individuals belonging to it. No dicotyledonous tree, 

 that I know of, produces its branches in whorls, such as we see in 

 Pinus and Abies. Can any of your readers inform me of an excep- 

 tion to the rule in these genera ; and whether any other genus is 

 confonnable to it ? In Larix this tendency does not appear to exist ; 

 it is not very obvious in Taxus ; and even in full grown trees of Pi- 

 nus sylvestris it seems to be absent. — Id. 



308. Vinca major. This appears to be one of the connecting links 

 between the Apocynaceae and the Asclepiadaceae. No British author 

 seems to have accurately described the pistillum, which has a very 

 curious structure. The so-called stigma, described in Smith's ' Eng- 

 lish Flora,' although it bears considerable resemblance to a genuine 

 stigma, cannot be considered to be such in reality, destitute as it is 

 of stigmatic fluid, and moreover surrounded and fenced by a copious 

 fringe of rough hairs forbidding the access of pollen. The style, 

 with its appendages, is spindle-shaped, much and suddenly dilated 

 in the thickened part, where there is a flattened edge nearly covered 

 with a dense pubescence, under which is an orange-coloured reflexed 

 membranous zone, covered with viscous fluid, and constituting, wholly 

 or in part, the true stigma. The remainder of the style above the 

 thickened part appears principally to serve the office of a pillar, to 

 support a canopy formed of the crested extremities of the anthers, 

 whose cells are lower in position than the stigma of Su ith, but higher 

 than the true stigma, the extent of which is somewhat doubtful. It 

 may either comprehend the whole edge of the thickened part, which 



