CA8TANEACEJE. 



923 



proper/ ■whilst they are shorter than the fruit in Betulaster.^ Some 

 thirty species are admitted in the genus ^ thus limited. 



The Alders^ (Fig. 158-167) differ hut little from the Birches with 

 which they were formerly united. The flowers are also monoecious 



Alnus cordifoUa. 



Fig. 162. Biflorous female 

 florifeious scale. 



Fig. 158. Foliaceous Tjranch 



Fig. 164. Long. sect, 

 of fruit. 



and disposed in catkins. In the axil of the scales of the male 

 catkin, there are generally three flowers forming a cyme, or, more 

 rarely, a single flower ; and the secondary scales, rising with the 

 flowers from the principal scale, are generally four in number, two 

 on each side. The perianth, sometimes but little developed, is formed 

 of four folioles, free or united at the base, and the stamens, equal in 



1 Sect. Subetula Eeg. Prodr. 162, sect. 1. 



2 Reg. Prodr. 179 (sect. 2). 



3 L. Spec. ed. 2, ii. 1193 ; Mantiss. 124.— 

 W. Spec. ir. 462. — Pali. Fl. Eoss. i. 60, t. 

 39, 40. — Ledbb. Fl. Hoss. iii. 649. — MicHX. Fl. 

 Bor.-Amer. ii. 180. — Koch, Syn. Fl. Germ. ed. 

 2, 760. — Trautv. et Mey. Middend. Seis. Fl. 

 Och. 81. — SoHKANK, Fl. Baical. 1. 421.— Fe. 

 Summ. Veg. Seand. i. 212. — Bge. Fl. Alt. Suppl. 

 Mem. Acad. Petersb. (1835), 506. — Cham. Linn<Ba, 

 V. 637, t. 6.— Wall. PI. As. Bar. ii. 7, t. 109. 



— Don, Prodr. Fl. Nep. 68. — Spach, Jacquem. 

 Voy. Bot. t. 168. — Sieb. et Zuoc. Abh. d. Keen. 

 Bttier. AK iv. Abth. 3, 228.— Miq. Ann. Mus. 

 Lugd.-Bat. ii. 136.— Gren. et Gode. Fl. dcFr. 

 iii. 146. 



* Alnus T. Inst. 687, t. 359.— Lamk. Diet. i. 

 330. — Nees, Gen. iv. t. 19. — Endl. Gen. n. 

 1841 ; Suppl. iv. p. ii. 20.— Spach, Ann. Sc. 

 Nat. ser. 2, xv. 124, 203 ; Suit. cbBuffon, xi. 246. 

 -Beg. Monogr. Betul. 73; DC. Prodr. xvi. 

 sect. ii. 180. 



