198 Rhodora [SEPTEMBER 
(No. 4475) are located near the Glen Echo lock of the Chesapeake 
and Ohio canal along the Potomac River. They are the very trees 
upon which the record of Aigeiros virginiana in Maryland was based. 
At the time I re-established this species I had never seen the tree in 
flower. Since that time my friend, Mr. Bartlett, has observed a 
number of trees along the Virginia shore of the Potomac River, 
some ten miles above Washington. 
A synopsis of our black poplars and their synonymy may be given 
as follows: 
Leaves of a cordate type. 
PoPULUS VIRGINIANA Fouger. Mem. Soc. Agr. Par. 1786: 
87, 1787. 
P. nigra B virginiana Castigl. Viaggio negli Stati Uniti 2: 334, 
1790. 
P. monilifera Ait. Hort. Kew. 3: 406, 1789? 
Michx. f. Hist. Arb. 3: 295, t. 10, f. 2, 1813. 
Watson, Dendr. Brit. 2: t. 102, 1825 (typical leaves). 
Schneider, l. c. f. 1: a-c, f. 3; n-n?. 
Aigeiros virginiana Tm. Elys. Mar. 3: 16, t. 3, f. B. 1910. 
Virginian Black Poplar. 
Pyramidal (when young), with spreading stout branches and a 
broad crown (when old): bark ashy-gray with a tinge of yellow; 
branchlets olive-colored or light-brown; buds light-brown, acuminate, 
scales ovate with a whitish margin, mucronate; leaves on somewhat 
reddish petioles, mostly cordate (1 dm. in length and fully as broad) 
acuminate, glabrous or nearly so on the upper face, sparingly pubes- 
cent on the lower face, margins pubescent, crenate-serrate from within 
2 cm. on each side of the petiole to within the same distance of the 
apex; staminate aments 1 dm. or less in length, scales laciniate, cadu- 
cous; flowers on pedicles 5 mm. more or less in length; stamens about 
30 in number, anthers yellow; fruiting aments 1 dm. or more in length. 
In P. virginiana the leaf-margin on each side of the petiole is nearly 
straight and entire: where it meets the petiole it forms an angle of 
about 120°, as shown in the illustration. 
Castiglioni (l. c.) held the Virginian poplar to be a variety of the 
black poplar of Europe, possibly on account of the dark green color 
of the leaves. That he regarded it identical with Populus virginiana 
Fouger. is evident from the following extract: 
