SALICACEAE. — POPULUS 39 
20. Populus tremula Linnaeus, Spec. 1043 (1753). 
Populus tremula, var. a typica Schneider, Ill. Handb. Laubholzk. 1. 19 
(1904). — Ascherson & Graebner, Syn. Mitteleur. Fl. IV. 25 (1908). — Gom- 
bocz in Math. Termesz. Közl. XXX. 126 (Monog. Gen. Populi) (1908). 
WESTERN SIBERIA. 
Populus tremula, var. Davidiana Schneider. See p. 24. 
Populus tremula, var. Davidiana, f. tomentella Schneider. See p. 25. 
21. Populus rotundifolia Griffith, Notul. Pl. As. IV. 382 (1854); Icon. Pl. As. 
IV. t. 546 (1854). — Dode in Mém. Soc. Nat. Autun, XVIII. (Extr. Monog. 
Inéd. Populus, sub Errata et Addenda, Espèce 34) (1905). — Gombocz 
in Math. Termesz. Kózl. XXX. 130 (Monog. Gen. Populi) (1908). 
Populi spec. Griffith, Itin. Notes, I1. No. 881 (1848). 
Populus microcarpa Hookqgr'f., Fl. Brit. Ind. V. 639 (1888). — Dode in Mém. 
Soc. Nat. Hist. Autun, Ni. (Extr. Monog. Inéd. Populus, 32, t. 11, fig. 34) 
(1905). e 
INDIA. Bhutan: W. Griffith (No. 4495). This specimen may be the type of 
Hooker's P. microcarpa: Bhutan, about Panga and towards Chupeh, alt. 2500 m., 
Griffith. 
Having seen only one fruiting specimen of the typical P. rotundifolia by the 
kindness of the Keeper of the Kew Herbarium, I cannot decide whether var. 
Duclouxiana Gombocz to which I have referred some of Wilson’s plants from 
Szechuan is sufficiently distinct. The shape of the leaves is variable, but the 
fruits of the type are very small, and the pedicels are glabrous. 
Populus rotundifolia, var. Duclouxiana Gombocz. See p. 25. 
SPECIES INCERTAE. 
Populus Bonati Léveillé in Monde Plant. XII. 9 (1910); in Fedde, Rep. Spec. 
Nov. VIII. 445 (1910). — Gombocz in Bot. Közl. X. 25, fig. (7) (1911). 
CHINA. Yunnan. 
Populus Bonati has been collected in Yunnan: Pa-ta-ouan, prés Pin Tchouan, 
March 3, 1907, Jean Py (No. 665 (type ex Léveillé), and according to Gombocz 
also by Ducloux at Tchong-chan. Gombocz considers P. Bonati a distinct species 
on account of its trilobed or trifid stigmas. His figures, l. c. p. 26, represent rather 
old female flowers of P. tremula, P. Bonati and P. adenopoda, and I have never seen 
such narrow and round stigmas on young flowers. The shape of the lobes of the 
stigmas seems variable even in the same species. The male flowers of P. Bonati are 
described with 12-15 stamens. In the flowers of typical P. adenopoda 1 have never 
found more than 7-9 stamens. I suggest that P. Bonati may be rather a form 
of P. rotundifolia, var. Duclouxiana than a form of P. adenopoda. 
Populus alaschanica Komarov in Fedde, Rep. Spec. Nov. XIII. 233 (1914). 
SOUTHERN MONGOLIA. Prov. Alashan: “ad ripas canalium irriga- 
torium et lacuum circa oppidum Dyn-juanj-in," I 27, April 15, June 4, 1908, 
Tshetyrkin (male and female types, ex Komarov). : 
According to the author this species belongs to Sect. Leuce, but I do not quite 
understand Komarov’s remark which follows: “An origine hybrida inter P. tre- 
mula L. et P. Przewalskii Max. (sect. Tacamahaca?) Populus tremula in vicinitate 
deest autem perfecte." The description is very short and rather insufficient. 
