NATIVE AMERICAN SPECIES. OF PRUNUS. 
. Serrations of the leaves rounded or obtuse (sometimes appar- 
ently acute by the presence of a pointed gland, rarely acute 
in P. subcordata Pacific coast species with incisely serrate 
leaves, and in P. orthosepala with glabrous leaves), mostly 
elandular, at least when they first unfold. Flowers with 
glandular calyx lobes, except in P. orthosepala and P. angusti- 
folia, species in which the calyx lobes are merely ciliate, and in 
P. venulosa with flowers only 6 to 7 mm. broad ........-------- 4, 
. Serrations of the leaves pointed or acute, the teeth mostly not 
gland tipped when the leaves unfold. Flowers with calyx 
lobes eglandular except sometimes inconspicuously glandular 
in P. americana. bie he a? eps AON Eee Bp 
. Leaves broadly oblong-ovate to pleualy chore, noe ai all 
trough shaped, the margin often doubly serrate. Flowers 2 
to 2.5 em. broad, the calyx usually with a reddish tinge, at least 
in age, the lobes lanceolate, conspicuously glandular-serrate... . - P. nigra. 
. Leaves ovate, ovate-lanceolate, oblong-lanceolate or sometimes 
oblong-oval (often orbicular in P. subcordaia, Pacific coast 
species) the margin rarely doubly serrate. lowers 8 to 15 
mm. broad, with calyx rarely or only slightly reddish, the lobes 
oblong-ovate, entire, glandular or eglandular.........---------- (fe 
. Leaves rather abruptly acuminate, the margins rather coarsely 
and deeply serrate. Flowers 18 to 25 mm. broad. Fruit red 
or reddish yellow, 18 to 30 mm. in diameter........ sais uheig si 6. 
. Leaves gradually acuminate or merely acute, the margins rather 
finely serrate. Flowers 6 to 14 mm. broad. Fruit purple or 
more rarely red or yellow, about 15 mm. or less in diameter.. 14. 
. Tree sprouting from the roots and forming thickets, bark scaly 
on older trunks; leaves glabrous or sparingly pubescent or in 
the subspecies tomentose below, acuminate even when they 
first unfold. Fruit ripening from August to October or in the 
PMMA BPONC OVALS <oc- os S Deletes 2s iss es teed esi P. americana. 
. Tree not sprouting from the roots and nat forming thickets, bark 
somewhat furrowed on older trunks; leaves usually strongly 
tomentose below, commonly somewhat obtuse when they first 
unfold. Fruit ripening in October and November, rarely 
in September, stone obovoid to nearly round .........-...-. P. mexicana. 
. Leaves orbicular to oval or rarely ovate, mostly obtuse at the 
apex, the margins incisely serrate, sometimes doubly so. 
OU Ch ST POPES TUNEROTOM esos 6 Metie thy cts he eS bee ile sad « P. subcordata. 
. Leaves ovate, ovate-lanceolate to oval, mostly acute at the apex, 
the margins crenate or crenulate, or at least not incisely ser- 
Peite MR OLNICES or LOvIe, MUN) OOM x Sis 21s 00 sae nt Uwe ono hae 8. 
. Leaves rather thick, ovate or ovate-lanceolate, only slightly lus- 
trous on the upper surface, veins usually conspicuous below, 
the margin rather coarsely and irregularly serrate........-...- 9. 
. Leaves usually rather thin, oblong-lanceolate to oval, lustrous 
on the upper surface, veins not very conspicuous, the margin 
pitclyesd GYyenly. BEIEALCI2 3) oc ico as - ye wen(o sie evade ee antes 12. 
. Tree not sprouting from the roots and not forming thickets; 
leaves 7.5 toll cm. long. Flowers 12 to 15 mm. broad....... P. hortulana. 
. Shrubs sprouting from the roots and forming thickets; leaves 
mostly 5 to7.5cm.long. Flowers 9 to 10 mm. broad........- 10. 
