IOWA ACADEMY OF SCIENCES. 



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Varies from a shrub-like tree, to a tree upward of twenty 

 feet in height; bark one-fourth inch thick, obliquely or lon- 

 gitudinally fissured, the outer layer separating in long brown- 

 ish-red scales; bark of the younger branches smooth, thin, 

 grayish-brown, len tides small, scattered; the branchlets 

 at first densely coated with fine white tomentum, which, 

 however, soon disappears; mature leaves ovate or trian- 

 gular, sometimes distinctly three-lobed, sharply serrate, 

 acute at the apex or occasionally rather blunt; base truncate 

 to subcordate, glabrous above and slightly puberulent or 

 glabrous below; one and one-half to three and one-half inches 

 long, three-fourths to two inches wide; borne on short, 

 slender petioles, one-half to one and one-half inches long; 

 young leaves are bronze in color, tomentose on both 



surfaces; spines thick, stout, 

 blunt; one-half to two inches 

 long, formed from aborted 

 or unproductive fruit spurs. 

 Flowers appearing after the 

 leaves, borne in bunches of 

 from four to six, on slender, 

 terete pedicels three-fourths 

 to one and one-half inches 

 long, and measuring one to 

 one and one-half inches in di- 

 ameter when opened fully; 

 petals, inserted remote, ovate, 

 crenately serrate or undulate 

 at the base, and somewhat 

 dentate toward the claw; calyx 

 sparsely without, and densely 

 tomentose within; fruit, five- 

 eighths to one and one-six- 

 teenth inches; form oblate or 

 roundish oblate, color not as 

 deep yellowish-green as loiven- 

 sis; skin thin, smooth, greasy, 

 specks large and fewer than in 

 lowensis, cavity shallow and 

 irregular with occasional pro- 

 tuberances, lined with heavy tomentum, stem three-fourths to 

 one and three-eighths inches; slender throughout, glandular, 



Figure 5. P. Coronarla, from Michigan, 



