Botanists have no choice but to regard some tendrils as leaf—, & others as stem-formations. ²

In Vitis there seems no room whatever for a doubt but that the tendril is an axial or stem-structure. Analogy with other plants buildt up of similar sympodia—as they are called—or superimposed axes³—& espec^y the tendency constantly shewn in some vines to bear flowers upon tendrils appear to me to settle their case sufficiently.—

Passiflora is much more perplexing. From analogy I sh^d. expect the nature of their tendrils to be similar to that of Gourd-tendrils.

Some, however, do look as tho’ they might be axillary branches. They may, however, be the modified first leaf of an axill^y. (or slightly extra-axill^y.) shoot.⁴

I do not recollect seeing any clear discussion about Passion-flower tendrils & have carefully examined them.—⁵

Clematis. The genus Naravelia (close to Clematis) has the terminal leaflet & upper lateral leaflets converted into tendrils like Pea.⁶