112 JOURNAL OF THE ARNOLD ARBORETUM (vol. iv 



known only in its staminate form. To this variety belong the two fol- 

 lowing forms: — 



X P. canadensis var. serotina f. erecta, comb. nov. 



P. monilifera erecta Selys-Longchamps in Bull. Soc. Bot. Belg. n. 11, 13 (1864). 

 P. canadensis b. erecta Dippel, Handb. Laubholzk. n. 200 (1892), excl. syn. of 



Carriere. 

 P. deltoides f. erecta Schneider, 111. Handb. Laubholzk. i. 7 (1904), excl. syn. 



of Carriere. 

 P. serotina var. erecta Henry in Elwes & Henry, Trees Great Brit. Irel. vn. 1817 



t. 385 (1913). 



A form with ascending branches forming a rather narrow pyramida 

 tree. 



X P. canadensis var. serotina f. aurea, comb. nov. 



P. canadensis aurea van Geerti Andre in III. Hort. xxiii. 26, t. 232 (1876). 



P. canadensis d. aurea van Geert apud Dippel, Handb. Laubholzk. n. 200 

 (1892). 



P. serotina var. aurea Henry in Elwes & Henrv, Trees Great Brit. Irel. vn. 



1817 (1913). 



A form with yellow leaves. 



X P. canadensis var. regenerata, comb. nov. 



"Peuplier regenere" Carriere in Rev. Hort. 1865, 58, 276. 



P. canadensis f. grandifolia h. hot. apud Dieck, Nachtr. Haupt-Verz. Zoeschen, 



1887, 16, nomen nudum. 

 P. canadensis regenerata Hort. ex Schelle in Beissner, Schelle & Zabel, Handb. 



Laubholz-Ben. 16 (1903) as synon. 

 P. regenerata Hort. ex Schneider, 111. Handb. Laubholzk. I. 7 (1904), as synon. 



of P. deltoidea. — Henry in Elwes & Henry, Trees Great Brit. Irel. vn. 



1824 (1913). 



This variety originated according to Carriere near Paris in 1814 It 

 is very similar to the preceding variety, but unfolds its leaves about a 

 fortnight earlier and is known only in the pistillate form. 



X P. canadensis var. marilandica, comb. nov. 



P. marilandica Bosc apud Poiret, Encvcl. Meth. Suppl. iv. 378 (1816) 

 Henry in Elwes & Henry, Trees Great Brit. Irel. vn. 1828, t. 409, f. 19 (1913). 



P. canadensis Hartig, Naturgesch. Forstl. Culturpfl. 436 (1851). 



P. euxylon Dode in Mem. Soc. Hist. Nat. Autun, xvni. 41. 69 (Extr. Mon. 

 Populus) (1905). 



This variety the history of which is unknown has probably the same 

 origin as var. serotina. It is a less vigorous trees of more spreading habit 



and resembles more P. nigra than its American parent, while var. serotina 



and var. regenerata are nearer the latter. 



X P. canadensis var. Eugenei hort. Simon-Louis freres apud Schelle in 

 Beissner, Schelle & Zabel, Handb. Laubholz-Ben. 16 (1903). 



"Peuplier Eugene" Carriere in Rev. Hort. 1865, 58, 



P. Eugenei Simon-Louis ex K. Koch, Dendr. n. 1, 493 (1872), pro forma P. 

 canadensis. — Mathieu in Gartenfl. xxxxvi. 675 (1887), sine descript. — 

 Schneider, 111. Handb. i. 9, (1904).— Sargent in Trees & Shrubs, n. 212 

 (1913).— Henry in Elwes & Henrv, Trees Great Brit. & Irel. vn. 1826, f. 

 409 f. 17 (1913). 



