ACEKACEAE. ACER 95 



woods, abundant, alt. 1800-2100 m., May and September 1907 (No. 

 274, in part) ; Hsing-shan Hsien, woods, abundant, alt. 1500-2100 m., 

 May 19 and October 1907 (Nos. 274, in part, 430); Kuan Pao, Chang- 

 yang Hsien, woods, alt. 1200-1800 m., December 1907 (No. 683, in 

 part, fruits); Patung Hsien, woods, alt. 1500-1800 m., May 1907 

 (No. 274, in part); South Wushan, woods, common, alt. 1200-1800 m., 

 May 11, 1907 (No. 274, in part). 



Part of No. 274 represents A. tetramerum, var. lobulatum Rehder (in Fedde Rep. 

 Nov. Sp. I. 174 [1905]) which passes gradually into the type and is perhaps better 

 considered only a slightly different form. This and the type are restricted to 

 Hupeh. The specimens of Szech'uan differ in their leaves being generally ovate to 

 ovate-oblong in outline, not or only very slightly lobed and usually 3-nerved at 

 the base. In regard to other characters they show marked differences, and the 

 following three varieties can be distinguished. 



Acer tetramerum, var. betulifolium Rehder, n. var. 

 Acer betulifolium Maximowicz in Act. Hort. Petrop. XI. 108 (1890). 



Western Szech'uan: Sungpan, woodlands, alt. 2400-2800 m., 

 August 1910 (No. 4511); southeast of Sungpan, alt. 3000-3200 m., 

 August 1910 (4512); Wa-ssu country, Wen-chuan Hsien, alt. 1800- 

 2400 m., July and September 1908 (No. 1901); alt. 2100-2500 m., 

 October 1910 (No. 4102). Kansu: banks of the river Lumbu, south 

 of Mt. Chagolo, July 11, 1885, S. N. Potanin. Northern Shensi: 

 G. Giraldi (Nos. 2118, 2119, 7137, in herb. Florence). 



With the recent material collected by Wilson hi northwestern Szech'uan at 

 hand I have come to the conclusion, that A. betulifolium cannot be separated 

 specifically from A. tetramerum. Sungpan is situated only about 80 miles south- 

 west of the type locality and W6n-chuan Hsien about 100 miles south of Sung- 

 pan, so that apparently the variety betulifolium is restricted to the northwestern 

 part of the range of the whole species. It is chiefly distinguished from the type 

 by its ovate or oblong-ovate leaves, not or only very slightly lobulate, glabrous or 

 glabrescent and usually three-nerved at the rounded or sometimes cuneate base 

 and by the broader wings of the fruits. 



Acer tetramerum, var. betulifolium f. latialatum Rehder, n. forma. 



Recedit a varietate praecedente praecipue racemis elongatis ad 18 

 cm. longis et alis latioribus leviter introrsum falcatis, ad 14 mm. latis. 



Western Szech'uan: southeast of Sungpan, woodlands, alt. 

 2400-3000 m., August 1910 (No. 4104, in part). 



A very striking plant in fruit with its long pendulous racemes and broad wings. 



Acer tetramerum, var. elobulatum Rehder, n. var. 



Acer tetrameram Rehder in Sargent, Trees and Shrubs I. 171, t. 85 (in part as 

 to the Szech'uan specimens and fig. 7) (1905). 



