34 WILSON EXPEDITION TO CHINA 
of Dah, July 3, 1856, Schlagintweit (No. 5327, sterile branch); Upshi to Gulab- 
Gárh, left side of Indus valley, June 28, 1856, Schlagintweit (No. 1563, old sterile 
branch); right shore of the Indus near Leh, July 4-9, 1856, Schlagintweit (No. 
1162, small part of young shoot); prov. Dras, Mülbe to Dras, October 8-11, 1856, 
Schlagintweit (No. 4976, old branch, distributed sub nom. P. laurifolia). 
There is another Himalayan specimen of Thomson’s from Zanskar in Tibet with 
young leaves and rather old female catkins. The ovaries or young fruits are deeply 
furrowed and glabrous, but the pedicels are rather longer and hairy. 1 am not 
quite sure about the value of the furrows and believe it is only an effect of drying. 
It seems very difficult to distinguish the Chinese P. szechuanica from this Tibetan — 
form, but nevertheless I should have treated the latter as a distinct species on . 
account of its geographical distribution had 1 not seen Wilson’s No. 4527, which 
shows the same pubescence and differs only in the more deeply cordate and round- 
ish leaves. 1 cannot refer the Chinese nor the Tibetan form to any of Dode's | 
species of this section ! or to a form described by previous authors. Populus tristis — 
of Fischer, which Koehne and Henry believed to be probably identical with these 
Tibetan specimens, seems to me quite distinct. Fischer says that he secured dried 
specimens from Sitka. I believe that P. tristis is very near to P. Mazimowiczii 
or to P. trichocarpa Hooker of western North America. 
10. Populus yunnanensis Dode in Mém. Soc. Nat. Autun, XVIII. (Extr. Monog. 
Inéd. Populus, 63, t. 11, fig. 103 a) (1905). 
SANA. Yunnan: without locality, F. Ducloux (Dode received a living 
plant). 
I have seen only young vigorous plants of this species raised from cuttings from 
Dode's type specimen.  Dode's description is insufficient; and I can only say 
that this species seems to be nearly related to P. szechuanica and needs f 
investigation. 
11. Populus Gamblei Dode in Mém. Soc. Nat. Autun, XVIII. (Extr. Monog. 
Inéd. Populus, 63, t. 12, fig. 103) (1905). — Haines in Jour. Linn. Soc. XXXVII 
407, fig. (1906). 
INDIA. Brit. Bhutan: district Darjeeling, Kalimpung, alt. 1300 m., March 
1875, J. S. Gamble (No. 26465; type, with old fruits; No. 6707; male co-type). 
This species was first mentioned by Gamble (Man. Ind. Timb. ed. 2, 690 [1902], 
without description. Dode bases his description upon male and female specimens 
collected by Gamble without citing any number, while Haines founded it upon 
Gamble's No. 2646* and 7607, of which I have before me excellent photographs 
and some male flowers and fruits kindly sent to the Arnold Arboretum by the 
Keeper of the herbarium of Kew Gardens. Haines says that it is extremely 
doubtful if Dode's imperfect description refers to his P. Gamblei, but 1 do not think 
that there can be the least doubt that both descriptions refer to the same plant. 
Dode's figure of the leaves agrees well with those of Haines' type specimen before 
me, he also mentions the puberulent perianth and the narrow bracts. I have not 
seen young female flowers, and unfortunately I have no leaves. Haines describes 8 
dimorphism of the leaves and shoots which, he believes, is possibly due to fungous 
agency. But, as far as I can judge from what he says, the appearance of large 
pubescent cordate leaves with two large glands just above the petioles on some 
branches while the normal leaves are quite glabrous, not cordate and without 
glands, may not be unusual in Populus, as the same variation occurs in Populus — 
1 The only species which might prove to be the same as var. tibetica is P. 
Jacquemontiana Dode, which I mentioned under P. ciliata Wallich, but Dode says 
“ ses capsules sont pubescentes.” 
