424 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



engelmannii Greene.) — Stems stout, unbranched. 0.5 to 1 meter high, rsually glabrous, 

 •very leafy; leaves mostly ovate. 5 to 10 cm. long, sessile, entire; heads few, in a 

 <corymb. the bracts pale, often purplish; rays few, pink or rarely lavender. 



The rays are not nearly so numerous as in our other species, and they are rather 

 -widely spaced. 



2. Aster conspicuus Lindl. Rough aster. Plate 52, A. Common at low and 

 middle altitudes, in thickets or thin woods, sometimes on open slopes. B. C. to 

 Oreg., Wyo.. and S. Dak. — Stems 30 to 60 cm. high, glabrous or rough, very leafy; 

 leaves 7 to 15 cm. long, obtuse or acute, thick, sessile; heads few or numerous, 10 to 13 

 mm. high; rays pale purple. 



3. Aster sayianus Nutt. Common at low and middle altitudes, in bogs, wet 

 thickets, or moist woods, sometimes among aspens or on open slopes. B. C. to Oreg., 

 Mont., and Alta. — Stems slender, 30 to 80 cm. high, hairy, usually purplish, very 

 leafy; leaves thin, 4 to 8 cm. long, entire or slightly toothed, sessile; heads few, 

 in a leafy cluster; rays usually deep purple, sometimes pale purple. 



4. Aster campestris Nutt. Occasional on the east slope at low altitudes, on dry 

 open hillsides or low flats. B. C. to Oreg., Colo., and Alta.^ — Stems 20 to 40 cm. high, 

 stiff and brittle, rough-hairy; leaves sessile, 2 to 4 cm. long; heads few or numerous; 

 rays bright purple. 



The plant blooms at the end of summer. 



5. Aster meritus A. Nels. Abundant above timber line on rock slides and open 

 slopes; occasional at middle or even low altitudes, on flats or open rocky slopes. 

 B. C. to Wyo. and S. Dak. — Plants 5 to 20 cm. high, often prostrate, usually forming 

 loose mats, the stems purplish, hairy; leaves 2 to 7 cm. long, finely hairy, entire or 

 toothed, sessile, obtuse or acute; rays purple to lavender. 



A showy plant, often conspicuous, especially on rock slides, forming great mats 

 •over the ground. It is abundant in sand along the river at Belton, but it is typically 

 an alpine species. 



6. Aster nelsonii Greene. Frequent on the east slope at low altitudes, on open 

 hillsides or rocky flats or in low thickets. Wash, and Oreg. to Mont, and Colo. — 

 Plants stout, 20 to 50 cm. high, the stems with mostly appressed hairs; leaves 4 to 7 

 ■cm. long, rough, thick; heads about 8 mm. high; rays pale purple. 



7. Aster polycephalus Rydb. Prairie at east entrance. Alta. to Ariz., Tex., and 

 Nebr. — Stems 20 to 50 cm. high; leaves linear, 2 to 5 cm. long, rough-hairy; heads 

 •6 to 8 mm. high; rays 4 to 5 mm. long. 



8. Aster exiguus (Fernald) Rydb. Occasional at low altitudes, on open slopes. 

 Wash, to Tex., Pa., and Vt. — Plants 10 to 40 cm. high, often branched, very leafy; 

 leaves linear or ol)long, 1 to 3 cm. long, "finely hairy, sessile; rays 3 to 4 mm. long. 



9. Aster crassulus Rydb. Dry banks at east entrance. Sask. to Calif., Colo., 

 and N. Dak. — Plants branched, 25 to 50 cm. high; leaves linear or linear-oblong, 

 2 to 5 cm. long, sessile, finely hairy; heads numerous, the bracts Ijroad, with spreading 

 tips; rays 4 to 6 mm. long. 



10. Aster laevis L. Common at low and sometimes at middle altitudes, on brushy 

 slopes, in woods, or on flats. B. C. to N. Mex., La., and Ont. — Plants pale green, 

 30 to 60 cm. high; leaves ovate or lanceolate, entire or toothed, the lower ones long- 

 etalked; heads few or numerous, 8 to 9 mm. high, the bracts very unequal, closely 

 oppressed ; rays pale blue or purple . 



A showy plant, abundant along the automobile road on the east side of the park, 

 ■often forming large dense patches. 



11. Aster occidentalis Nutt. Belton, in sandy thickets. Yukon to Calif, and 

 <^olo. — Plants 20 to 60 cm. high, nearly glabrous; leaves entire or toothed, bright 

 ^reen; heads numerous; rays pale purple. 



