534 Rosaceae Crataegus 



Leaves of flowering branches mostly oblong or rhombic, often unsymmetri- 

 cal, with 4 or 5 pairs of strongly ascending veins, not deeply im- 

 pressed; fruit 5-10 mm in diameter; styles and nutlets usually 5 



III. VlRIDES. 



Leaves of flowering branches usually one to one and a half times as long as 



wide (except in forms of no. 10) TV. Rotundifoliae. 



Leaves of flowering branches abruptly narrowed, rounded, truncate, or subcordate 



at the base, mostly ovate, oblong-ovate or elliptic, broadest at or below the 



middle, usually lobed or incised. 



Leaves of flowering branches usually slightly narrowed or abruptly acuminate 



at the base; petioles and inflorescence conspicuously glandular; usually 



shrubs V. Intricatae. 



Leaves of flowering branches usually rounded to subcordate at the base; petioles 

 and inflorescence eglandular or slightly glandular; arborescent shrubs or 

 trees. 

 Leaves thin; fruit 7-9 mm in diameter, with small, sessile calyx; flowers 12-15 



mm in diameter VI. Tenuifoliae. 



Leaves firm to subcoriaceous; fruit usually 10-20 mm in diameter; flowers 



16-25 mm in diameter. 



Fruit with thin flesh and relatively large nutlets, remaining hard and dry; 



fruiting calyx large and elevated (except in no. 18) . . .VII. Pruinosae. 



Fruit becoming mellow or succulent, usually edible; fruiting calyx smaller, 



sessile or nearly so. 



Leaves barely firm; petioles and primary veins slender; fruit glabrous; 



styles and nutlets usually 3-4 VIII. Coccineae. 



Leaves firm to subcoriaceous; petioles and primary veins stout; fruit 

 pubescent at least toward the base; styles and nutlets usually 5.... 



IX. MOLLES. 



Fruiting calyx deciduous; fruit 5-7 mm in diameter, bright red, long persistent after 

 maturity; flowers about 10 mm in diameter, often not opening until early June. . 



X. CORDATAE. 



Nutlets pitted on ventral surfaces; fruit 6-12 mm in diameter, often long persistent 



after maturity; flowers usually opening after the middle of May 



XL Macracanthae. 



KEY TO THE SPECIES 



I. CRUS-GALLI Loud. 



Leaves of flowering branches mostly of a spatulate or obovate type, broadest above the 

 middle. 

 Leaves thick and glossy (except sometimes in shade), those of flowering branches 

 1-2.5 cm wide, usually obtuse, rounded or short-pointed at the apex. 



Leaves of flowering branches mostly 1.5-2.5 cm wide 1. C. criis-galli, p. 537. 



Leaves of flowering branches mostly 1-1.5 cm wide 



la. C. criis-galli var. pyracanthifolia, p. 537. 



Leaves thinner, shining above, usually pointed or acuminate at the apex 



2. C. pyracanthoides var. arborea, p. 537. 



Leaves of flowering branches broader, mostly oblong-obovate or elliptic, usually broad- 

 est about the middle. 

 Leaves thick, those of the flowering branches usually acute or acuminate at the apex; 



fruit obovoid or ellipsoid 3. C. regalis, p. 538. 



Leaves thinner, those of the flowering branches usually rounded or short-pointed at 

 the apex; fruit subglobose 4. C. acutifolia, p. 538. 



