=1.= =Betula lùtea= Michaux filius. Birch. Yellow Birch. Plate 32. Medium size trees; bark of small trees and of the branches of old trees smooth, silver or dark gray, freely peeling off in thin strips, becoming on older trees a dark brown, rarely tight, usually fissured into wide plates and rolling back from one edge; the shoots of the year hairy, greenish gray, becoming glabrous or nearly so and reddish-brown by the end of the second year, not aromatic when bruised but when chewed sometimes a faint wintergreen odor can be detected; winter buds pointed, reddish-brown, the lower scales more or less pubescent, generally with a fringe of hairs on the margins; leaves usually appearing in pairs, ovate to ovate-oblong, 4-14 cm. long, taper-pointed, oblique and wedge-shape, rounded or slightly cordate at the base, sharply and rather coarsely serrate, hairy on both sides when they appear, becoming at maturity glabrous or nearly so above, and remaining more or less pubescent below, especially on the veins, both surfaces with few to numerous resinous dots; petioles permanently hairy, generally 5-13 mm. long; flowers appear in May; staminate spikes in clusters at the ends of the branches, about 6 cm. long, scales broadly ovate, blunt, fringed with hairs, green-tipped with a margin of reddish-brown; pistillate spikes solitary in the axils of the leaves, mature spikes 2.5-5 cm. long, generally 2.5-3 cm. long, commonly about half as thick as long, recurved to ascending, commonly about horizontal, sessile or on short stalks; scales very variable, 5-11 mm. long, generally 7-8 mm. long, sometimes as wide as long but generally about one-fourth longer than wide, densely pubescent on the back, or rarely glabrous on the back, ciliate, glabrous or nearly so on the inside, commonly with a few brown or black glands on the margin, commonly lobed to more than one-third of their length, lobes ascending or divaricate, the lateral generally the larger and almost as long as the narrower middle lobe; nuts divested of the wings, slightly obovate, about 3 mm. long, wings about two-thirds as wide as the nut and usually with a fringe of hairs at the blunt apex. [Illustration: Plate 32. BETULA LUTEA Michaux filius. Yellow Birch. (× 1/2.)] =Distribution.=--The distribution of this species is variously given as from Newfoundland west to Manitoba and south in the Alleghenies to Georgia. It is now definitely known that the species of _Betula_ hybridize which may account for the peculiar forms often encountered. That there are geographic races or Mendelian segregates of this species is evidenced by the different interpretations given this species by different authors. _Betula alleghanensis_ Britton appears to be one of them. The descriptive difference between _Betula lenta_ and _Betula lutea_ is not clear, which has resulted in many authors crediting _Betula lenta_ to Indiana and the area west of Indiana.