498 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Corolla large, blue, purple, or white, the tube 
much shorter than the calyx; stamens re- 
curved .........2-2--22--2.--2. wee eeeeee 2. Eustoma (p. 499). 
Styles stout and short or none; stamens straight. | 
Corolla with nectariferous glands, pits, or scales. 
Corolla campanulate; flowers yellow; low 
annual...........-22222-2- 0.0.22 eee eee 3. HALenta (p. 499). 
Corolla rotate; flowers yellow or blue; per- 
ennials. 
Style manifest; leaves verticillate; co- 
rolla with a crown at the base... .. 4. FRAsERA (p. 499). 
Style wanting; leaves opposite, occa- 
sionally alternate; corolla without 
@ CTOWN. ......-.---.---22.-02--- 5. SWERTIA (p. 500). 
Corolla without nectariferous glands, pits, or 
scales. 
Calyx parted to near the base; corolla rotate 
or nearly so; stamens inserted on the 
base of the corolla....................-10. PLheuroGyNa (p. 503). 
Calyx merely lobed; corolla not rotate; 
stamens inserted in the corolla tube. 
Corolla without plaits or lobes at the 
sinuses; calyx without an inter- 
calycine membrane; sepals im- 
bricated. 
Flowers 4-merous, rather large, us- 
ually over 3 cm. long; corolla 
lobes fringed or toothed; in- 
ner sepals broader, mem- 
branous-margined............. 6. ANTHOPOGON (p. 501). 
Flowers 5-merous (seldom 4-merous), 
small, less than 2 cm. long; 
outer sepals broader; corolla 
lobes never fringed, rarely 
toothed ...--.................. 7. AMARELLA (p. 501). 
Corolla plicate in the sinuses, the plaits 
more or less extended into mem- 
branous lobes or teeth; calyx with 
an intercalycine membrane, its 
lobes valvate. 
Dwarf annuals or biennials; flowers 
solitary, terminal; anthers cor- 
date, versatile. .............. 8. CHONDROPHYLLA (p. 502). 
Perennials; flowers short-peduncu- 
late, at least some of them 
axillary; anthers linear or ob- 
long, extrorse................. 9. DAsysTEPHANA (p. 502). 
1. CENTAURIUM Hill. Crenraury. 
Low branched annuals with bright rose pink flowers; calyx 4 or 5-parted, with 
slender keeled divisions; corolla salverform, with 4 or 5 lobes; stamens 4 or 5, 
partly adnate to the corolla tube; anthers twisted at maturity; ovary 1-celled; stig- 
mas 2; capsule 2-valved, oblong. 
