47 



2. Populus heterophylla Linnaeus. SWAMP COTTONWOOD. 

 SWAMP POPLAR. Plate 16. Tall trees up to 5-8 dm. in diameter- 

 bark of old trees very thick, broken into long ridges which are separated 

 by deep furrows, reddish-brown but generally weathered to ash-color; 

 shoots densely woolly at first, becoming glabrous before the second 

 season; leaves broadly-ovate with petioles 2-10 cm. long, more or less 

 woolly on both surfaces on unfolding, becoming glabrous above and 

 remaining woolly beneath, at least on the larger veins, rarely becoming 

 entirely glabrous, usually cordate at the base, blunt at apex, margins 

 rather regularly crenate-serrate; flowers in April; capsules ripening in 

 June, about 6 mm. in diameter, on stalks 5-10 mm.- long; wood same as 

 the next species. 



Distribution. Along the Atlantic Coast from Connecticut to 

 Florida and along the Gulf to Louisiana, and northward along the 

 Mississippi Valley to Michigan. It is found in many parts of Indiana. 

 In the northern counties it is found in "gumbo" soils in swamps. It is 

 a common tree in the river swamps of the lower Wabash Valley where it 

 reaches its greatest size. There are no records for the extreme south- 

 eastern part of the State, although it has been found in swamps in 

 Harrison and Clark Counties and is found in many countiee of Ohio. 



Remarks. The pith of the shoots of this species is orange which 

 easily distinguishes it from all other species of the genus which have 

 a white pith. This species in all of its range is closely associated 

 with the common cottonwood, and millmen make no distinction in the 

 price or qualities of the timber. 



3. Populus deltoides Marshall. COTTONWOOD. CAROLINA POP- 

 LAR. (Populus balsamifera var. tiirginiana (Castiglioni) Sargent). 

 Plate 17. One of the largest trees of the Indiana forests; bark of very 

 old trees very thick, broken into ridges up to 1 dm. or more in thickness, 

 separated by deep furrows, reddish-brown, weathering to a gray; leaves 

 hairy on both surfaces as they unfold, soon glabrous except on the 

 margins which are more or less ciliate, broadly-deltoid, usually 7-12 

 cm. long, and about as wide, base more or less truncate or cordate, or 

 somewhat wedge-shaped, with rather short acuminate tips, crenate- 

 serrate; capsules ovate, about 6 mm. in diameter, on stalks 1-2 mm. 

 long; wood light, soft, weak, sap wood white, heartwood small and 

 brown; warps badly on drying. 



Distribution. Quebec to Florida and west to the Rocky Mountains. 

 Throughout Indiana in low ground along streams, in swamps and about 

 lakes. On account of its habit of growing only in low ground it is 

 infrequent in the hill country of southern Indiana. 



Remarks. The cottonwood is adapted to a moist soil, propagates 

 easily, grows rapidly and is one of the best trees for forestry purposes 



