Tap. 8298. 
POPULUS NieRaA, var. BETULIFOLIA. 
hen 
Origin uncertain, 
SALICACEAE. 
Poru.us, Linn,; Benth. et Hook. f. Gen. Plant. vol. iii. p. 412. 
Populus nigra, Linn., var. betulifolia, Torrey, Fl. New York, vol. ii. p. 216; 
a forma typica petiolis et ramulis junioribus pubescentibus differt. 
Arbor, 9-25 m. alta; truncus rugosissimus, 0°5-1 m. (rarissime ad 1°75 m.) 
diametro, comam magnam ovoideam ferens; ramuli juniores plus minusve 
ubescentes, flavi, vetusti cinerascentes, gemmis pallide brunneis. Vo/ia 
eltoideo-rhomboidea, 6-10 em. longa, 5-8 cm. lata, apice longe attenuato- 
acuminata, basi Jate cuneato-rotundata, rarius truncata vel levissime 
cordata, serrulata, saepe primo pubescentia cito glabrescentia, supra 
saturate viridia, infra paulum pallidiora; petioli ad 6 cm. longi, primo 
pubescentes. Amenta mascula 2°5-5 em. longa. Squamae late obovatae, 
circiter 4 mm. longae, laciniis 1-75 mm. longis instructae. Antherae saepe 
11-17. Amenta feminca gracilia, 7-10 em. longa. Pedicelli 2-3 mm. longi. 
Capsulae ovoideae, 5-7 mm. longae.—P. nigra, var. betulaefolia, Wesmael 
in DC. Prodr. vol. xvi. pars 2, p. 328. P. nigra, var. hudsonica, C. K. 
Schneider, Ill. Handb. Laubholzk. vol. i. p.5, fig.4m,n. P. nigra, Michx, 
Fl. Bor.-Am. vol. ii. p. 244, au Linn. VP. hudsonica, Michx f. Hist. Arb. 
Am. vol. iii. p. 298, tab. 10, fig. 1, et N. Am. Sylva, vol. ii. p. 114, tab. 96, 
fig. 1. PP. betulifolia, Pursh, Fl. Am. Sept. vol. ii. p. 619; Loudon, Arb. et 
Frat. Brit. vol. iii. p. 1656, fig. 1516, et Encycl. Trees and Shrubs, p. 825, 
fig. 1501; Dode, Extr. Monogr. Inéd. Gen. Populus, p. 48.—8. A. SKAN. 
The downy-twigged Black Poplar of English collections 
is readily distinguished from the smooth-twigged tree com- 
monly grown in gardens as Populus nigra by its more 
- compact, rounded, Elm-like head, and by a greater tendency — 3 
to develop huge burrs on its old boles. But many forms - 
intermediate in facies between these two trees are to be 
met with; among these intermediates the pubescence, the — 
presence or absence of which is so distinctive of the extreme 
types, varies remarkably in degree and duration without 
being uniformly correlated with differences in habit. The 
examination of many specimens from different trees conveys 
the impression that the pubescence can hardly be relied — 
upon as affording a varietal character. If this conclusion — 
be just, the status usually accorded to the downy Black 
Frsrvary, 1910. 
