34 WILSON EXPEDITION TO CHINA 



of Dah, July 3, 1856, Schlagintweit (No. 5327, sterile branch); Upshi to Gulab- 

 Gdrh, left side of Indus valley, June 28, 185G, Schlagintweit (No. 1563, old sterile 

 branch); right shore of the Indus near Leh, July 4-9, 1856, Schlaginiiveit (No. 

 1162, small part of young shoot); prov. Dras, Mulbe 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 

 Bhows 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. Pojpulus 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. Maximowiczii 

 or to P. trichocarpa Hooker of western North America. 



10. Populus yunnanensis Dode in Mem. Soc. Nat. Autun, XVIII. {Extr. Monog. 

 Ined. Populus, 63, t. 11, fig. 103 a) (1905). 



CHINA. 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 further 

 investigation. 



11. Populus Gamble! Dode in Mem. Soc. Nat. Autun, XVIII. (Extr. Monog. 

 Ined. 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. 2646"*; 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 Hames founded it upon 

 Gamble's No. 2646'' and 7607, of which 1 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 I 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 a 

 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 



^ 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." 



