REPORT ON THE MOSSES OF THE ABOR 
EXPEDITION, 1 9 1 1 - 1 2 
By 
II. A. Dixon, m.a., f.l.s. 
[Editorial Note : — The Abor Hills constitute “a, section of the Himalayan range 
lying on the northern frontier of Assam, between the Siom river on the west and tho 
Dibang on the east, occupied by tribes of 'i ibeto-Burman origin.” (Imperial Gazetteer 
of India 1908, V, 9.) 
A punitive expedition was despatched against the Abors towards the end of 19*11. 
Several officers of the Scientific departments of the Government of India were per- 
mitted to accompany the expedition and amongst them was Mr. I. H. Burkill, M.A., 
F.L.S , lately Economic Botanist to the Botanical Survey of India, and now Director 
of the Botanical Gardens in tho Straits Settlements. The mosses collected by Mr. 
Burkill were sent to Mr. II. N. Dixon, M.A., F.L.S., for determination, and the 
following report has been kindly contributed by the latter.] 
The mosses collected by Mr. Burkill were not numerous, amounting 
to a little over BO numbers ; but for the size of the collection they pre- 
sented a considerable degree of interest, including some half-a-dozen 
undescribed species besides a few which indicated an interesting 
extension of geographical range. The most notable perhaps of these 
is Claop odium crispulum Broth. ( Bseudoleskea crispula Bry. jav.), 
which has hitherto been recorded only from Java and Formosa. Cardot 
in the Mousses de F ile Formose (Beihefte zum Bot. Contralbl., Bd. XIX, 
Abt. II, 1005), in giving some account of the general distribution of the 
mosses of that island, has drawn up a list of 15 species which are 
common to Formosa, the Himalayan range, and the Malayan Archipelago, 
with six others found in the two former regions but not known at pre- 
sent from Malaysia. This relationship supports, so far as it goes, the 
evidence afforded by Phanerogams and Vascular Cryptogams as to the 
geographical affinities of the flora of the Assam region. Drude (Handb. 
der Pflanzengeographie, p. 479), divides the Indo-Malayan tract into 
ten floral regions > the 5th and 6th being — 
5. Birma (Pegu, Cachar, etc., nord warts sieh mit der Tropenregion 
des sudostl. Himalaya mischend). 
6. Siam — Annam mit Formosa und dem nordostlichen Auslaufern des 
imdischen Reiches, 
These two regions merge together in Assam, from the south and east, 
while from the west the flora of the great Himalayan range intrudes ; 
and these three floral zones are represented among the bryophytes 
equally with the higher plants ; indeed even the comparatively small 
