498 
Upkof. — Contributions towards a Knowledge of 
An intermediate, as far as anatomical construction is concerned, between 
rhizophore and stem has not been observed, although the writer studied 
thirty-five such so-called transformed rhizophores of different species. More- 
over, they are all distinctly positively heliotropic from the very start, while 
on the contrary all rhizophores or aerial roots, as has been stated, are 
Fig. II. i, stem of S. uncinata : A, branches instead of rhizophores; B, rhizophore formed by 
such a branch ; 2 , cross-section of stem a in 1 ; 3, cross-section of ordinary stem ; 4, cross-section of 
rhizophore B in 1 ; 5, epidermis and hypodermis of ordinary rhizophore ; 6, the same of rhizophore 
b in 1 ; 7, cross-section of young rhizophore ; 8, cross-section of a young root with root-hairs ; 
9, epidermis of stem ; 10, the same of rhizophore ; 11, branching system. 
negatively heliotropic, an argument in favour of their root nature which is 
beyond doubt. 
The same indications are shown in Fig. Ill, 3-8, in Selaginella grandis, 
which are even more characteristic than in S. uncinata ; as the stem of the 
former has a strongly developed system of vascular bundles which manifests 
itself also in the small shoot, whereas the rhizophore and root have a small 
