26 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



with incurved tips, fewer and coarser than in its hybrids. Stigmas 3 or 4. 

 Stamens 50 to 60. 



4. Fopnhis deltoidea, Marshall, var. missouriensis, Henry, in 

 Gardeners' Chronicle, Ivi. 46 (i8th July 1914). 



Twigs angled. Leaves similar in shape to the last, but larger, 5 to 6 inches 

 wide and long ; petiole and both surfaces pubescent, some of the pubescence 

 persisting in summer ; basal glands 3 or 4. Stigmas 3 or 4. Stamens 50 

 to 60. 



5. Populus an^ulata, Alton, Hort. A'eisj., iii. 407 (1789). 



[Popiihis deltoidea, var. missoiiriensis x Popiihis nigra var. typica. ] 



Twigs angled. Leaves similar to the last, but longer than broad and 

 differing in the rounded or acute apex, deeply cordate or truncate at the 

 base, glabrous except for the pubescent petioles ; basal glands 3 or 4. Flowers 

 with small, dentate scales. Stigmas 4. Stamens 50 to 60. 



*** Glands variable at the base of the leaf, absent or one or two in number. 



Hybrids between the European P. nigra and the American P. deltoidea 

 var. monilifera.'^ Leaves with irregular marginal cilia, which are often 

 sparse and usually deciduous in summer ; serrations not coarse and not 

 sinuate. 



t Branchleis glabrous. 



6. Popttlus serotina, Hartig. 



Branches ascending, wide-spreading. Leaves unfolding latest of all the 

 poplars and with a red tint, ovate-deltoid, about 3 inches wide, with a broad 

 truncate base. A staminate tree ; stamens 20 to 25. 



7. Populus regenerata, Schneider. 



Similar to P. Eugenei in habit ; with foliage like that of P. serotina, but 

 unfolding a fortnight earlier. A pistillate tree ; stigmas usually only 2. 



8. Populus Eugenei, Simon-Louis. 



A narrow columnar tree with short ascending branches. Leaves unfolding 

 early with a reddish tint, smaller than those of P. serotina, broadly cuneate 

 at the base, with a slender sharp-pointed non-serrated acuminate apex. A 

 staminate tree ; stamens about 20. 



9. Populus marilandica, Bosc. 



A tree with irregular branches. Leaves early in unfolding, rhomboid, 

 cuneate at the base, tapering into a long acuminate apex. A pistillate tree ; 

 stigmas variable, 2, 3, or 4. 



^ P. robusta excepted. 



