182 ON THE DISARTICULATION OP BRANCHES. 



are gradually compressed to almost a horizontal line, and at last 

 become obliterated. 



In reply to some questions with reference to Castilloa elastica^ 

 I have received the following information from Mr. B. Cross, the 

 well-known collector of Caoutchouc, Cincliona^ and other plants. 

 He states that in the forest the young Castilloas push up stems 

 to a great height, and during the progress of growth throw out at 

 variable distances a number of simple leafy shoots. These, on be- 

 coming mature, begin to wither in succession from the oldest or 

 lowest, and finally separate by an articulation. At last, however, 

 branches are produced which bear fruit and do not drop off. 

 Sometimes the trunk, after running up to a certain height, divides 

 into two or three stems, each furnished with numerous short stiff 

 upright branches, which are permanent and ripen fruit abundantly. 

 Probably, however, the "abortive" shoots are produced during 

 the entire growth of the tree. Mr. Cross does not consider these 

 to be " true" branches. He says that the wood is not properly 

 formed, the buds are imperfectly developed, and from these the 

 plant cannot easily be propagated. All this perhaps arises from 

 the nourishment being required for the ascending growth — a con- 

 clusion borne out by the plants at Kew, which show that a given 

 bud may grow into an erect permanent branch, or into a horizonal 

 deciduous branch, according to the requirements of circumstances. 

 The latter, if taken in time, appear, under cultivation, to strike as 

 freely as the permanent branches. The character of a branch is 

 evidently brought about by the direction of its growth. 



In the preceding cases the disarticulatory branches have not a 

 leaf-like appearance ; in Vitis macropus (woodcut) they bear flowers 

 and fruit, but never, as before said, in Castilloa^ or perhaps in the 

 case of Antiaris. In the following cases, however, the deciduous 

 branches are very leaf-like (in some instances have been described 

 for leaves) and bear flowers and fruit. The examples laid before 

 the Society are PTiyllanthus {Ecidid) glaucescens anA P. jugVandi- 

 folius) ; further instances may be found in other species of the 

 genus and in the allied genera of Cicca^ Sauropus, &c., all belong- 

 ing to Euphorbiaceffi. The leaf-like branches of these plants have 

 much in common with true leaves ; they fall off in the same way, 

 and have buds in their axils which alone continue the permanent 

 branching of the plant ; the stem also is swollen at the base, as are 

 many petioles. It must be remarked that branches arc always 

 axillary in production, and in these cases are subtended by 



