1919] SARGENT. NOTES ON NORTH AMERICAN TREES, V. 61 



NOTES ON NORTH A3IERICAN TREES. V^ 



C. S Sargent 



Populus tacamahacca Mill. — This name has recently been taken up^ 

 for the Balm of Gilead or Ontario Poplar, Popzihis candicans Ait. Miller's 

 description, however, of Populus tacamahacca, *' foliis subcordatis, inferne in- 

 canis," applies equally well to the common Balsam Poplar of northeastern 

 North America. In his detailed description Miller speaks of the leaves as 

 *' differing from each other in shape and size, most of them almost heart- 

 shaped, but some are oval and rather nearer to spear-shaped. In the Bal- 

 sam Poplar the leaves vary from ovate to lanceolate, and are subcordate, 

 rounded or cuneate at base, and are not broad-ovate, deeply cordate and 

 abruptly pointed at apex, as are the leaves of P. candicans Ait. Miller de- 

 scribes the staminate flowers of his P. tacamahacca, but as only pistillate 

 trees of P. candicans have been seen, his description of the staminate flowers 

 cannot apply to that species. According to Aiton P. candicans was not 

 introduced into England until about 1772, or fourteen years after Miller's 

 description of his P. tacamahacca was published. The evidence certainly 

 seems to show therefore that Miller included in his description of Popu- 

 lus tacamahacca the different forms of the Balsam Poplar which all authors 

 but ^liller have called P. halsamijera and for which Miller's name should 

 be adopted. 



With the material found in herbaria which I have seen it has not been 

 possible to determine the western range of Populus tacahamacca, for with- 

 out the pistillate flowers or the fruit it is impossible to distinguish this species 

 from the western P. irichocarpa Torr., and specimens with leaves only col- 

 lected in ^Montana, Idaho, northern California and on the coast of Alaska 

 can be equally well referred to one of these species as to the other. 



Populus tacamahacca var. Michauxii Farwell in Rhodora, xxi. 101 (1919). 

 P. candicans Sargent, Silva N. Am. ix. t. 490, f. 1, 2 (staminate flowers), 

 (1896), not Aiton.— P. Michauxii Dode, Extr. Monog. Ined. Populus, 62, 

 (1905), — P. habamifcra var. Michauxii K, Henry, Gard. Chron. ser. 3, lix. 

 230 (1916). — This is a common northern variety with cordate or subcordate 

 leaves slightly pilose on the under side of the midribs and veins, and dis- 



foundland and the shores of Hudson Bay. 



Quebec 



Populus acuminata var. Rehderi, n. var. 



A typo rccedit foliis majoribus plerisque longius petiolatis, ramulis 

 junioribus et gemmis pubescentibus, fructibus minoribus. 



A large tree with smooth gray or greenish yellow bark, becoming deeply 



^ The preceding parts of this series have appeared In Botanical Gazette: I. Qiiercug. 

 (lxv. 423-459. 1918). — II. Carya. (lxvi. 229-358. 1918). — 111, Tiha. (lxvi. 428-438, 494- 

 511. 1918). — IV. (lxvii. 208-242. 1919). 



2 Fanvell in Rhodora, xxi. 101, 1919. 



