i895. NOTES AND COMMENTS. 383 



fringes or cilia, not unlike the Tamenta of ferns," in front of the 

 petioles and true stipules. When the latter fall, the plant appears to 

 possess only these fringes. In a member of an allied family — Paliunis 

 australis (Rhamnaceae) — they are again dimorphic, but here spiny in 

 both cases, serving two purposes. On the strong, upright, young 

 stems they are largest and longest, being slightly decurved, and nearly 

 equal in size. On the slenderer lateral shoots they are very unequal 

 and dissimilar. Those on the upper side of the branches are longer^ 

 long-pointed, and straight, and arranged in two ranks, one to the right,, 

 the other to the left of the shoot. On the lower face, they are short 

 and decurved, or hooked. It is suggested that, while the straight ones, 

 serve to protect the plant from browsing animals, the hooked ones 

 will, in addition, help it to climb or scramble among the bushes or 

 shrubs. The enlargement of some of the stipules in certain acacias 

 to form great horn-like structures, which are generally hollow with a 

 small opening, and, in America at least, usually tenanted by colonies 

 of stinging ants, is an interesting and often-cited case in myrme- 

 cophily. Similarly, the greatly enlarged leaf-sheath turned up at the 

 edges, in some species of Smilax, forms a pocket, in which, as Burck 

 has already pointed out, ants come to live. Burck, however, believes 

 this development to be quite independent of the necessity for bud- 

 protection, and merely the result of the benefit accruing to the plant 

 from the presence of the ants. The base of the petiole in Korthalsia, 

 a rattan palm, is developed into a large hollow ocrea (or sheath) which 

 ants use as a home. In this case, at any rate, it is impossible to 

 conceive of any benefit resulting to the plant. 



Apart from certain cases of biological importance akin to those 

 cited above, Sir John's paper is useful in pointing out the existence of 

 stipules in exceptional cases, or in genera and species in which they 

 have hitherto been undescribed. 



African Orchids. 



If the plants brought home by Mr. Scott Elliot from his recent 

 trip to Central Africa and Mt. Ruwenzori prove as interesting 

 throughout as the orchids and asclepiads have done, he is much to be 

 congratulated on the results of his expedition. The October number 

 oi the. Journal of Botany conidims the conclusion of an account of the 

 orchids by Mr. Rendle and the first part of a description of the 

 asclepiads by Mr. R. Schlechter. Among other novelties in the latter 

 family we notice a new genus, while of the orchids a large percentage 

 have been hitherto unknown to botanists. Most of these belong ta 

 typical tropical African genera like Lissochilus, Eulophia, Angy^cnniy 

 Polystachya, Hahcnaria and the like, but in one case Mr. Elliot's plant 

 gives a widely extended area to its genus. Epipactis (helleborine) is 

 a name well known to British botanists, and by the discovery of a new 

 species {E. afvicana) at 8,000 to 10,000 feet on Mt. Ruwenzori, the 



