Notes on some of the Climbing-Plants near Desterro, 



in South Brazil 1 ). 



Aus einem Briefe an C. Darwin. 

 Hit Tafel XXVII. 



In your Paper on the "Movements and Habits of Climbing-Plants", you say 

 that you have seen no tendrils formed by the modification of branches, and you 

 even seem to entertain some doubt whether such tendrils exist. In the genus 

 Strychnos, the tendrils are called by Endlicher ramuli cirriformes, and I have now 

 satisfied myself that they really are of this nature. On the branches of upright 

 shoots of a Strychnos which grows here, the tendrils are disposed in a very 

 regular manner. On the branches, the leaves of the first, third, fifth, &c. pairs 

 are horizontal, those of the second, fourth, and sixth pairs are vertical in relation 

 to the main axis; and it is from the angles of every under leaf of these latter 

 pairs that the tendrils spring. Now, on the points commonly occupied by tendrils, 

 true branches are sometimes developed. The leaves from the angles of which 

 the tendrils spring are often much reduced in size, while in other cases they are 

 but little or not at all changed. Each tendril bears near its tip a pair of rudi- 

 mentary leaves ; and whilst very young the tendrils are straight, but soon become 

 curved downwards and rolled into a helix, whether they have clasped a support 

 or not. This Strychnos is a very inefficient climber; the short stiff tendrils but 

 rarely catch anything. . 



A member of the Hippocrateaceae, probably a Tontelia, is likewise a branch 

 climber. One of its branches, three feet in length, had not as yet developed 

 leaves, and resembled a gigantic tendril, with most of its lateral branchlets already 

 grasping neighbouring objects. From the angles of the tendril-branches, other 

 branches arise, which as far as I have seen, are not sensitive, and never clasp 

 anything. This latter arrangement must be serviceable to the plant; for such 

 branches grow upright without being arrested in their course, whilst the plant is 

 secured by the tendril-branches. 



Caulotretus, one of the Leguminosse, offers another case of tendrils being 

 formed from modified branches. In the species which I observed, the branches 

 bear tendrils only in the angle of their first leaf, and this leaf is always rudi- 

 mentary. In young shoots it might, at first sight, be thought that tendrils spring 

 from the axils of all their leaves. In this plant every tendril appears to consist 



i) Journal of the Linnean Society of London. Bot. 1865. IX. p. 344 349. PL IX. 



