492 WILSON EXPEDITION TO CHINA 



ENUMERATIO ALNORUM ASIAE ORIENTALIS 

 NEC NON HIMALAYAE. 



Subgenus I. CREMASTOGYNE Schneider, n. subgen. (descriptio in clavi). 



Abius, sect. Cremastogyne Winkler in Engler, Pflanzenr. IV. -61, 102 (1904). 



I raise this group to the rank of a subgenus because it is Hke subgen. Alnaster, 

 different from all the groups of the subgen. Alnus. Winkler did not know the 

 male flowers and the ripe fruits. Both the male and female inflorescences are 

 single and axillary, but both appear in the spring from the same young branch- 

 lets, while in the subgen. Alnus they develop in the autumn. In the subgen. Al- 

 naster only the female flowers appear in the spring after or with the leaves. The 

 male flowers of the subgen. Cremastogyne are much reduced. One dichasium con- 

 sists of only one bract; the bractlets being apparently wholly united with it or 

 wanting, and 4 (sometimes 5 ?) single stamens without any remains of petals 

 which are present in all the other subgenera. The bracts are ciliate, the thecae 

 of the anthers are separated and a little hairy, and the filaments are very short. 

 The seeds have broad wings as in the subgen. Alnaster. 



1. Alnus cremastogyne Burkill. See p. 488. 



2. Alnus lanata Duthie. See p. 488. 



Subgen. II. ALNUS Endlicher, Gen. Suppl. II. 28 (1842); Suppl. IV. pt. 2, 

 20 (1847), includ. subgen. C'lethropsis. 



This subgenus includes all the true Alntis sensu Spach with the male and female 

 inflorescences appearing in the summer or fall on the same branchlet, which does 

 not elongate as in the subgen. Cremastogyne. The male flowers are above the female, 

 and both open in autumn in some of the species, while in most of them the amenta 

 remain closed during the winter and open in spring before the leaves appear. Even 

 in the autumn-floWering species the cones ripen the following year. The sect. Cle- 

 thropsis, as far as I see, cannot be separated as a different subgenus from Alnus. I 

 can always distinguish 3 flowers in each dichasium, and the petals seem to be partly 

 connate at the base and partly free as in A. maritima Muhlenberg, which also 

 flowers in the autumn. See also my remarks under sect. Clethropsis and sect. 

 Gymnothyrsus. 



Sect. 1. GYMNOTHYRSUS Spach in Ann. Sci. Nat. ser. 2, XV. 204 (1841). — 

 Endhcher, Gen. Suppl. IV. pt. 2, 21 (1S47). — Regel in De Candolle, Prodr. XVI. 

 pt. 2, 184 (1868). — Matsumura in Jour. Coll. Sci. Tokyo XVI. art. 5, 7 {Rev. 

 Alni Spec. Jap.) (1902). — Winkler in Engler, Pflanzenr. IV.-61, 110 (1904). 



Alnus, sect. Clethra W. D. Koch, Syn. Fl. Germ. Helv. 663 (sine descriptione) 

 (1837); ed. 2, 762 (1843). — Hayek, Fl. Steierm. 1. 108 (1908). 



Alnus Spach in Ann. Sci. Nat. s^r. 2, XV. 203 (1841). 



Almis, subgen. Euclethrus Petermann, Deutschl. Fl. 516 (1849). 



Alnus, sect. Euahius Regel in Nouv. Mem. Sac. Nat. Mosc. XIII. 134 (Monog. 

 Betulac. 76) (1861). 



Alnus, sect. Alnaster Regel, 1. c. 133 (75) (1861), quoad A. nitidam. 



Alnus, subgen. Gymnothyrsus Regel in Bull. Soc. Nat. Mosc. XXXVIII. pt. 

 2, 425 (1865). — Prantl in Engler & Prantl, Nat. Pflanzenfam. III. pt. 1, 

 46 (1887). — Dippel, Handb. Laubholzk. II. 147 (1892). — Koehne, Deutsche 

 Dendr. 112 (1893). — Calher apud Schneider, III. Handb. Laubholzk. I. 

 124 (1904). — Winkler in Engler, Pflanzenr. IV.-61, 102 (1904). — Ascher- 

 son & Graebner, Syn. Mitteleur. Fl. IV. 416 (1911). 



Alnus, sect. Alnus Sargent, Silva N. Am. IX. 68 (1896). 



