OROHIDEJEJ. 389 



jsome of tlie islands over which the bridge was built were one 

 season covered with this Orchis^ specimens of which Avere sent 

 to me by Captain Clerk, and which are now in the Herbariuni 

 at Kew/' A parcel of the tubers of E. camj^rstrfs was sent ta 

 one of us from the Native State of Sirohi, with the object of 

 ascertaining their commercial value if collected as Salep ; they 



were similar in form to those of E. nudaj but smaller^ and bore 

 no resemblance to the commercial article. 



Description. — The tubers of E. virens are eonico-obp} ri- 

 form, surrounded with circular marks showing the insertions of 

 old leaves ; if they have been exposed to the air, as is often the 

 case with the upper portion of the tuber, they are of a greenish 

 colour, when not so exposed of a yellowish white. In the fresh 

 state many fleshy fibres issue from the lower portion of the 

 tuber. E. nnda has larger tubers^ often much flattened, in 

 structure and colour they resemble those of E, virens^ the leaves 

 are larger, and the flowers often purple, though in some 

 specimens they are green like those of E. "eirens. The tubers 

 of E. campestris are of a similar character. Under the micros- 

 cope the gum cells are seen, and the exterior cells contain 

 bundles of raphides. The small tubers exhibit starch granules, 

 but in large tubers these are entirely absent. 



Chemical composition. — The fresh tubers contain a large 

 quantity of clear white mucilage, which is not precipitated by 

 ferric chloride or neutral acetate of lead, but is precipitated by 

 basic acetate of lead and alcohol. The mucilage, unlike that of 



' > 



salep, is not coloured violet by iodine solution. Nitric acid 

 forms no mucic acid when allowed to act upon the gum. The 

 ash of the dried tubers amounted to 3*6 per cent, 



DENDROBIUM MACRAEI, LimU. 



Fig. — Xeu. OrcJiid. »/., t. 118. 



Hab. — Sikkim, Kliasia Mts., The Concan, and Nilgiri Hills. 

 Tlie plant. 



Vernacular.— ZixQXvii, Jiba-sag {Hind.), Jibai, Jibanti {Beng.\ 



Jivanti [Mar., Gnz.). 



