270 LEGUMINOSAE (PEA FAMILY) 



turbinate; its lobes entire, glabrous witUin and nearly so without: petals 

 obovate: fruit not known. — On the Cache La Poudre, near Fort Collins, 

 Colorado. 



4. Prunus melanocarpa (A. Nels.) Rydb. Bull. Torr. Bot. Club 33: 143. 

 1906. An erect slender shrub or small tree 1-5 m. high: leaves ovate or 

 oblong-ovate, abruptly acuminate, rounded or somewhat cordate at base, 

 smooth or nearly so on both sides, the teeth of the fine serration incurved 

 or appressed; petioles not glandular: raceme compact, erect or. ascending: 

 fruit when fully mature black, always more or less astringent. P. demissa, 

 which probably belongs wholly to the northwest of our range. — This is the com- 

 mon Chokecheery in the central Rocky Mountains. 



5. Prunus pennsylvanica L. f. Suppl. 252. 1781. Tree 4-8 m. high, with 

 light red-brown bark: leaves oblong-lanceolate, pointed, finely and sharply 

 serrate, shining, green and smooth both sides: fruit globose, fight red, very 

 small, with thin and sour flesh; stone globular. Wild Red Chebry. — From 

 Colorado, northward and eastward to Newfoundland. 



6. Prunus Besseyi Bailey, Bull. Cornell Expt. Sta. 70: 261. 1894. A low 

 shrub with spreading or prostrate branches, often only a few dm. high: leaves 

 oblong to oval, the teeth appressed, either acute or obtuse at base and apex: 

 flowers in sessile umbels, expanding with the leaves, about 1 cm. broad: 

 fruit large, 12-15 mm. in diameter, yellowish-red, juicy, scarcely astringent, 

 edible. Sand Cherry. — From the western plains to the foothills of the Rocky 

 Mountains. 



57. LEGUMINOSAE Juss. Pea Family 



Herbs, shrubs, or trees with alternate and usually compound leaves, irreg- 

 ular flowers, 5 sepals more or less united, 5 very dissimilar petals (upper 

 petal or standard larger than the others and inclosing them iu the bud, turned 

 back or spreading; the two lateral petals or wings oblique; the two lower 

 petals coherent by their edges and forming the keel which usually incloses the 

 stamens and pistil), usually 10 variously united stamens (mostly 9, united into 

 a tube and the upper one separate, rarely 9 or 5), and a 1-celled ovary becom- 

 ing a more or less elongated pod. Style generally inflexedor incurved. Seeds 

 mostly with thick cotyledons and without endosperm. 



Stamens 10. wholly distinct. 



Leaves digitately 3-foUolate; flowers yellow 1, Thermopsis. 



Leaves odd-pinnate; flowers white . 2. Sophora. 



Stamens (some or all) miited by their filaments at least at base, i, e., 

 monadelphous or diadelphous. 

 Anthers of 2 forms; stamens monadelphous; leaves digitately 5- or 



more-foliolate • . 3. Lupinus. 



Anthers all alike, reniform. 



Leaves odd-pinnate, without tendrils. 



Fod not a loment, 2-valved or indehiscent. 

 Foliag;e not glandular dotted. 



Digitately 3-foliolate or rarely 5-foliolate. 



Leaflets entire .4. Lotus. 



Leaflets serrulate or denticulate. 

 Flowers in racemes ....... 5. Melilotus. 



Flowers capitate or in short loose spikes. 



Pods curved or coiled 6. Medicago. 



Pods straight, membranous 7. Trifolium. 



Finnately 5- or more-foliolate (rarely simple or 3-foUolate 

 in no. 9). 



Shrubs 8. Robinia. 



Herbs, or rarely with ligneous base. 



Keel of the corolla blunt 9. Astragalus. 



Keel of the corolla acute 10. Aragiulus. 



Foliage glandular-dotted. 



Pod with hooked prickles . . • . • • .11. Glycyrrhiza. 

 Pod not prickly. 



Shrubs 12. Amorpha. 



Herbs, or merely with ligneous base. 



