POMACEAE. 5 J 9 



Fruit 10-12 mm. in diameter, glaucous or pruinose. 

 Leaves firm, shining. 



Fruit globose ; western. 14. C. nitida. 



Fruit pyriform ; eastern. 15. C. Porteri. 



Leaves thin, dull. 16. C. pruinosa. 



^ower surfaces or teeth of the leaves, pedicels and calyx pubescent or glandular. 

 Leaves deeply pinnately incised ; fruit 4-6 mm. long. 17. C. apiifolia. 



Leaves serrate or lobed ; fruit 6-25 mm. long. 

 Leaves glabrous, or nearly so. 



Leaves, or most of them, truncate or cordate at the base. 



18. C. coccinea. 

 Leaves, or most of them, narrowed at the base. 

 Fruit S-14 mm. in diameter. 



Fruit globose to oval; leaves firm in texture. 



Bractlets and calyx very glandular. 19. C. rotundifolia. 

 Bractlets and calyx pubescent. 20. C. occidentalis. 



Fruit pyriform ; leaves thin. 21. C. tenui/olia. 



Fruit only 6-8 mm. in diameter. 22. C. macracantha. 



Leaves pubescent, especially along the veins beneath. 



Leaves ovate-orbicular, mostly truncate or cordate at base. Fruit 1.5- 



2.5 cm. in diameter; red. 23. C. mollis. 



Leaves ovate to oval, mostly cuneate or narrowed at the base. 

 Fruit globose or depressed -globose. 



Veins not prominent on the lower leaf-surfaces. 



24. C. Biltmoreana. 

 Veins very straight and prominent. 25. C. campgstris. 



Fruit oval to oblong. 



Fruit dull red, over 1 cm. long. 26. C. tomentosa. 



Fruit bright red, 1 cm. long or less. 27. C. Chapmani. 



Fruit pyriform. 28. C. pyriformis^ 



* * Corymbs I-7-flowered. 



Calyx-lobes not incised ; petioles and leaf-serrations very glandular. 



29. C.flavd, 



Calyx-lobes deeply incised ; petioles and leaf-serrations little or not at all glandular 

 Leaves obovate or spatulate, obtuse. 30. C. u?tiflora t 



Leaves oval, mostly acute at both ends. 31. C. Vailiae. 



1. Crataegus Crus-galli L. Cockspur Thorn. Newcastle Thorn. 

 (I. F. f. 1 99 1.) A shrub or small tree, the branches spreading. Thorns numerous, 

 slender, 5-10 cm. long; leaves coriaceous, shining above, obovate or oblanceolate, 

 obtuse or abruptly acuminate at the apex, cuneate at the base, 2-5 cm. long, sharply 

 serrate; flowers about 12 mm. broad; calyx-lobes linear-lanceolate; styles usually 

 1-3; fruit globose or slightly pear-shaped, about 12 mm. long. In thickets, Que- 

 bec to Manitoba. N. EL, Fla. and Tex. May-June. 



2. Crataegus brevispina (Dougl.) Farwell. Douglas Thorn. A small 

 tree. Foliage glabrous or nearly so. Leaves obovate, unequally serrate or some- 

 what lobed. cuneate or narrowed at the base, 4-8 cm. long, the petiole about one- 

 fourth the length of the blade ; thorns 1.5-3 cm. l° n gl flowers about 2 cm. wide; 

 calyx-lobes ovate, obtuse, rarely glandular; fruit globose, purple-black, I— 1. 5 cm. in 

 diameter. Mich, to Br. Col., Colo, and Ore. May-June. [C. Douglasii Lindl.] 



3. Crataegus spathulata Michx. Small-fruited Haw. (I. F. f. 1992.) 

 A -hrub or small tree. Spines 2-5 cm. long; leaves fascicled, coriaceous, shining 

 above, rather dull beneath, spatulate. obtuse and crenate or with 2-3 lobes at the 

 summit, entire and cuneate at base, almost sessile, 2-4 cm. long; flowers about 8 

 mm. broad : calyx-lobes ovate ; styles commonly 5 ; fruit red, globose, 46 mm. 



In thickets, Va. to Fla.. Mo. and Tex. May-June. 



4. Crataegus Brownii Britton. Addison Brown's Thorn. Glabrous 

 throughout. Leaves obovate or oval- obovate, obtuse, or obtusish at the apex. 

 cuneate-narrowed at the base, irregularly crenate, with distinctly rounded teeth, 

 slender-petioled, 4-6 cm. long ; pedicels slender; bracts linear, very glandular; 

 flowers about' 1.5 cm. broad ; calyx-segments linear-lanceolate. Va. and W. Va. 

 May. Type from Buchanan. Va. 



5. Crataegus berberifolia T. & G. Barberry-leaved Thorn. Similar 

 to C. Crus-galli, but the young Leaves, pedicels and calyx densely pubescent. 

 Thorns slender. 2-5 cm. long; mature leaves pubescent with scattered hairs, rather 



