POPULUS 



2750 



3134. 



Eastern cotton- 

 wo od. Populus 

 deltoides var. moni- 

 lifera. (XH) 



New Mex., Ariz, and S. Calif.), is P. mexicana, Wesm. 

 (P. MacDougalii, Rose): a taU tree, sometimes 80 ft.: 

 Ivs. longer-pointed, the petioles not flattened: fls. 

 shorter-stalked than in P. Wislizenii and longer than 

 in P. Fremontii: caps. ^-J^in. long: it is closely related 

 to P. Fremontii, differing chiefly in the larger disk of 



the pistillate fls., 

 in the rhombic 

 Ivs. of the young 

 shoots and 

 which often ap- 

 pear with the 

 deltoid Ivs. on 

 old shoots. S.S. 

 14:71. 



11. deltoides, 

 Marsh. (P. del- 

 toidea, Auth. ). 

 SOUTHERN 

 COTTONWOOD. 

 CAROLINA POP- 

 LAR. Large na- 

 tive tree with 

 deeply furrowed 

 or ridged dark- 

 colored or gray- 

 brown bark in mature speci- 

 mens, and a deliquescent habit 

 (top breaking up into many 

 strong branches of about equal 

 importance), the branches 

 wideyspreading and the top 

 relatively thin and open: 

 branchlets usually terete except 

 on very strong shoots: Ivs. 

 large, triangular-ovate, very 

 broad in proportion to their length, mostly trun- 

 cate or nearly straight on the base, abruptly acumi- 

 nate, coarsely crenate-dentate with mostly curved 

 sinuses, but the margin plane or flat, the petiole long, 

 much flattened near the blade and commonly with 

 2 or 3 glands at the top, the stipules small and falling 

 early: catkins long and loosely fld., the scales large, 

 dilated at apex and filiform-lobed; stamens 40-60; 

 stigmas and placenta? 3 or 4: fr. an 

 ovoid acute caps. Generally distributed 

 from Que. to the plains region and south 

 to Md. and possibly farther. S.S. 9:494, 

 495. A variable group; although famil- 

 iarly known, the specific characters are 

 not clearly defined. The species takes on 

 somewhat unlike forms in the S. and N. 

 and W. Marshall meant to designate the 

 southern form, which has the following 

 characters (P. deltoidea var. missouriensis, 

 Henry. P. angulala, Auth., not Ait. P. 

 deltoidea var. angidata, Sarg.) : twigs 

 angled: Ivs. deltoid-ovate, 5-6 in. wide and 

 about the same length, at the base 

 shallowly cordate or truncate, at the apex 

 short - acuminate and cuspidate, when 

 young and even to midsummer pubescent 

 on both surfaces and petiole; margins 

 sinuate-dentate, the teeth few and coarse 

 and with incurved tips; basal glands 3 or 4. 

 S. E. U. S. and in the Mississippi Valley, 

 from Mo. southward. 



Var. monilifera, Henry (as P. deltoidea 

 var. monilifera. P. monilifera, Ait.). 

 NORTHERN COTTOXWOOD. Figs. 3134- 

 3137. Twigs usually not angled: Ivs. 

 smaller, on average normal shoots about 

 3-4 in. wide and of similar length da- 

 brous on both surfaces and petiole (or 

 only a few evanescent hairs along midrib 

 175 



and nerves), the basal glands usually 2. Canada to Pa. 

 and probably farther south. 



Some of the cult, forms of this group are fairly dis- 

 tinct in foliage and aspect, and they appear to be 

 associated with particular horticultural names in the 

 nurseries. A golden-lvd. tree is known as var. Fan 

 Geertii or var. aurea (really a form of P. serotind) . This 

 is one of the best of yeflow-lvd. trees, and generally 

 holds its color throughout the season. Like all trees of 

 this unusual character, it should be used cautiously, 

 and the best effects are obtained when it is planted 

 against a group of trees so as to appear as if naturally 

 projecting from the other foliage. Some of the most 

 ornamental specimens of cottonwood are those with 

 reddish If .-stalks and midribs. Taking all things into 

 consideration, the cottonwood is one of the best of 

 the poplars for general ornamental planting. It grows 

 rapidly and in almost every soil, and yet it possesses 

 elements of strength and durability which most of the 

 poplars lack. Its foliage is always bright and glossy, 

 and the constant movement of the broad rich green 

 Ivs. gives it an air of cheeriness which few trees possess. 

 This tree or P. 

 Sargentii has been 

 much used on the 

 prairies and in 

 western towns, 

 much too abun- 

 dantly for good 

 landscape effects. 

 The rapid growth 

 of the tree gives a 

 feeling of luxuri- 

 ance to planta- 

 tions even when 

 most other trees 

 appear to be 

 weak or starved. 

 The cottonwood 

 thrives best on 

 rather low lands, 

 and yet it is gener- 

 ally an admirable 

 tree for high and 

 drier areas. Spon- 

 taneous forms of 

 introduced hy- 

 brids have proba- 

 bly been confused 

 with P. deltoides, obscuring the definition of the 

 species, as, particularly, P. Eugenei and P. angulaia. 



A poplar in Mont, and Idaho allied to this species 

 has been provisionally referred to P. Besseyana, Dode 

 (Bull. Torr. Club, 39:302). The If .-bases are rounded 

 or subcuneate and more or less serrate; glands small; 

 petioles flattened. "In P. Sargentii, the Ivs. are flabel- 

 jate-cordate, with an open concave sinus at base, which 

 is toothless. The Ivs. much resemble P. acuminata 

 but are broader and less cuneate at the base, and in the 

 latter species the petioles are terete." It is probable, 

 however, that P. Besseyana, Dode, is P. angulata, Ait. 



12. Sargentii, Dode (P. deltoides var. occidentalis, 

 Rydb. P. occidentalis, Brit. P. monilifera var. occi- 

 dentalis, Henry). GREAT PLAINS COTTONWOOD. Lvs. 

 usually smaller and with relatively longer abrupt 

 acumination, broader at base and with fewer rather 

 coarser teeth: young branches light yellow, shining: 

 buds often pubescent: pedicels shorter than the caps. 

 The Great Plains or xerophytic form, Neb. to Dak., 

 Sask., Alberta and to New Mex.; frequent along 

 stream-beds. S.T.S. 2:583. Doubtfully specifically 

 separable from P. deltoides. 



(a) P. Andrewsii, Sarg. (P. acuminata X P. Sargentii). Raised 

 by E. H. Andrews, Colo., from a cutting taken from a wild tree: Ivs. 

 oblong-ovate, gradually or abruptly long-pointed and acuminate, 

 rounded or occasionally abruptly cuneate at the broad base, finely 

 serrate except at apex, thin, bright green and shining above and 



3136. Young tree of Populus deltoides 

 var. monilifera, showing the spreading 

 open growth. 



