MYRICA. JJKTULA. 
299 
2. P. canescens (Sm.); 1. routulisli angularly toothed cottony 
and white beneath, 1. of the young shoots cordate-ovate undi- 
vided, stiff. 8. — E. B. Hi 19. — A large tree with suekers. L. not 
lohed except occasionally the youngest. Scales of the catkins 
dee])ly cut at the end. — Damp woods. T. IV. Gray Poplar. E. 
3. P. tremula (L.) ; 1. nearly round acute serrate glabrous on 
both sides, young 1. slightly downy, stiff. 4 erect auricled in pairs. 
— E. B. 1909. — A rather large tree, produeing numerous suckers. 
Peduncles vertically compressed. Scales of the catkins deeply 
])almately cut. Stig. erect, each pair furnished with a common 
descending wavy lobe. — Woods. T. III. IV. Aspen. 
4. P. niffra (L.) ; 1. trianyular acuminate serrate glabrous, 
“catkins lax cylindrical, stiff. 4 simple spreadinff." — E. B. 1910. 
— A large tree without suckers. L. remarkably triangular. Young 
shoots glabrous. Scales of the catkins palmately cut smooth. — 
Damp places, river-hanks. T. III. Black Poplar. 
Tribe II. Myricea. 
3. Mtrica Linn. 
1. M. Gale (L.); 1. lanceolate broader upwards sen-ate, st. 
shrubby. — E. B. 562. — Height 3 — 4 feet. Bushy. Catkins ses- 
sile, erect. Fr. vidth resinous glands. L. fragrant when bruised. — 
Bogs. Sh. V. Sweet Gale. Boff Myrtle. 
Tribe III. Betulinea. 
4. Betula Linn. Birch. 
1. B.alba(L.); l.rhomboid-trianffulardouh\yseTva.tea.hnnptly 
acuminate, scales of the fern, catkins 3-lobed : lateral lobes de- 
flexed, fr. obovate-elliptical shorter than the rounded membranous 
maryin. — E. B. 2198 (upper fig.). B. alba Koch. B. verrucosa 
Fries ! — L. usually glabrous, often covered with resinous spots 
above, always having a manifest tendency to a rhomboidal form. 
A'oung shoots mostly with resinous tubercles. Stip. ovate-lan- 
ceolate, acute, thriee as long as broad, circinate ; sides not de- 
flexed. Buds conical. Readily distinguished from the following 
by its leaves. Young twigs often very long and pendulous. — 
Rather common. T. IV. V. White Birch. 
2. B. fflutinosa (Fries!); 1. cordate-ovate unequally serrate 
acute, scales of the fern, catkins 3-lobed : lateral lobes ascending, 
fr. broadly obovate as lony as the rounded membranous maryin . — 
E. B. 2198 (lowerfig.). B.pubescens Koch. — L. usually glabrous 
always more or less ovate. Stip. ovate, blunt, twice as long as 
broad; sides deflexed. Buds ovate. Not so elegant a tree as 
the preceding and often httle more than a bush. Twigs some- 
