204 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. IX. 



The cultivated crops are buckwheat, millet and a little maize. After the 

 grain is sown no care is taken to keep fields in proper cultivation. One en- 

 closed plot was full of ganja plants (Cannabis indica) in splended condition. 



From Yoksun I marched to Tumlong through tropical and sub-tropical vege- 

 tation similar in all respects to that of the Darjeeling district. 



By camparison with the drier regions of Upper Sikkim which I afterwards 

 visited, I considered that the main characteristic of the vegetation along the 

 Singalelah Range is its poverty in variety of forms and its superabundant 

 wealth in individual species of Rhododendrons. I only collected about 200 

 species of plants in flower and fruit. There was, however, evidence to prove 

 that the floral harvest would have been more remunerative later in the season. 

 Sir J. D. Hooker, in his appendix on the Physical Geography of Sikkim, 

 states : "The banks (of rivers) between 8,000 and 14,000 feet are generally 

 covered with Rhododendrons, sometimes to the total exclusion of other wooded 

 vegetation, especially near a snowy mountain, a cool temperature and great 

 humidity being the most favourable conditions for the luxuriant growth of 

 this genus." Such conditions prevailing throughout the Singalelah Ranges 

 due to its proximity to Kinchinjunga, account for the overwhelming abundance 

 of Rhododendrons, and may also be accepted as probable reasons for the 

 comparative absence of herbaceous plants (in ordinal and generic forms) 

 which are unable to maintain a struggle for existence in such an adverse 

 climate and against such formidable competitors. 



Second Tour. — The Lachung Valley. — I arrived at Tumlong on the 7th July, 

 and was detained there until the 24th waiting for supplies which where delayed 

 by the break of communications caused by the excessive rains. 



Immediately on their receipt I commenced my second excursion and marched 

 through the hot tropical valley of the Teesta, arriving at Choongtam, at the 

 junction of the Lachen and Lachung rivers, on the 28th. Near Choongtam a 

 remarkable transition from tropical to temperate vegetation takes place with 

 no palpable increase of elevation. Cnicus involucratus, Astragalus pyonorhizus, 

 Eupaturium cannabinum, Anemone vitifolia, and a few other plants served to 

 accentuate the change. Leptocodon gracilis, a fragile climber with blue flowers 

 rambled over bushes everywhere. I collected many specimens of Pleopeltis 

 rhynchophylla from a tree at the end of the Lachung cane bridge. 



The hill above Choongtam ascends abruptly to 10,000 feet, and is almost 

 entirely clad with grass alone. It forms the termination of a lofty range 

 running southwards from Kinchinjhow, and divides the Lachen and Lachung 

 valleys. The Tibetans aver that this long spur possesses but one practicable pass, 

 namely, the Sebo La between Momay Samdong and Tungu ; but by dint of per- 

 sistent enquiry I discovered that there are at least two more —one from Lach- 

 ung to somewhere near Latong, the other from Yeumtong to Tallum Samdong. 

 I was informed that they are rarely used, a fact explained by the lack of the 

 necessity of frequent intercourse between the inhabitants of the two valleys. 



