2 88 On some Brazilian Climbing-Plants. 



and when covered with their bluish-purple flowers, this Securidaca is one of the 

 most elegant and magnificent plants of our flora. 



From the last two plants it is but one step to the primordial and simplest 

 condition of branch climbers, exhibited by the numerous species which scramble 

 up a thicket without twining and without the aid of rootlets, hooks, or tendrils. 



Thus we can trace in the development of branch climbers the following 

 stages: - 



1. Plants supporting themselves only by their branches stretched out at right 

 angles - - for example, Chiococca. 



2. Plants clasping a support with their branches unmodified Securidaca 

 (Hippocratia according to Endlicher, Gen. Plant. No. 5700, "arbores v. frutices, 

 ramis contortis scandentes"). 



3. Plants climbing with the tendril-like ends of their branches. According 

 to Endlicher (Gen. PI. No. 5745), this is the case with Helinus ("ramulorum apicibus 

 cirrhosis scandens"). 



4. Plants with highly modified tendrils, which may, however, be transformed 

 again into branches - - for example, the above-mentioned Papilionaceous plant. 



5. Plants with tendrils used exclusively for climbing Strychnos, Caulotretus. 

 I will here add a few miscellaneous observations. You describe some species 



of Bignonia in which the tips of the tendrils become enlarged and adhesive after 

 remaining for a short time in contact with some object; but the trifid tendrils of 

 Haplolophium , one of the Bignoniacese , terminate (without having come into 

 contact with any object) in smooth shining disks, which, however, after adhesion, 

 sometimes become considerably enlarged. In Cardiospermum you state that the 

 common peduncle which bears the subpeduncles with the flower-buds and the 

 pair of short tendrils, although it spontaneously revolves, does not bend on contact 

 or contract spirally; hence it may be worth mentioning, as showing a difference 

 in the action of the tendrils in related genera, that in Serjania the common peduncle 

 contracts spirally when the single tendril which it bears has clasped, as frequently 

 happens, the plant's own stem. 



With respect to spirally twining plants, you state that though the Hibbertia 

 dentata sometimes revolves in one direction and sometimes in the other, yet it 

 invariably twines from left to right. But in another genus belonging to the same 

 family, namely the Davilla, the stem twines indifferently from left to right or 

 from right to left; and I once saw a shoot, ascending a tree about five inches 

 in diameter, reverse its course in the same manner as so frequently occurs with 

 Loasa. Although individuals, as we have just seen, in some few cases twine in 

 opposite directions, yet you say that you have not as yet met with any case of 

 two species in the same genus twining in opposite directions, and you are able 

 to give only two cases of species within the same natural order thus twining. 

 But a Mikania growing here twines from right to left, whilst the Mikania scandens 

 described by you twines in an opposite direction; and I believe that there are 

 species of Dioscorea which twine in opposite directions. Lastly, with respect to 

 the thickness of the support which can be ascended by spirally twining plants, 

 I have lately seen a trunk about five feet in circumference which was thus 

 ascended by a plant apparently belonging to the Menispermaceas. 



