WOOTON AND STANDLEY—FLORA OF NEW MEXICO. 749 
129. BARTLETTIA A. Gray. 
Slender annual, nearly glabrous, with long-petiolate rounded repand-dentate 
leaves and long-pedunculate, rather large heads, these heterogamous, radiate; invo- 
lucre campanulate, of 12 to 14 oblong-lanceolate bracts in 2 or 3 series; achenes 
cuneate-oblong, compressed; pappus of numerous unequal bristles in a single series. 
1. Bartlettia scaposa A. Gray, Mem. Amer. Acad. n. ser. 5; 323, 1854. 
Type Locatity: On a prairie near Corralitas, Chihuahua. 
Rance: Southern New Mexico, south into Mexico. 
New Mexico: Lordsburg (A. Davidson 1422). 
130. MESADENIA Raf. 
Perennial herb; leaves thrice pinnatifid into narrow segments; heads 10 to 15 mm. 
high, numerous, in corymbiform cymes; involucre turbinate, of a single series of 5 
or 6 narrow bracts; flowers 5 or 6, with white corollas, none radiate; achenes glabrous. 
1. Mesadenia decomposita (A. Gray) Standley. 
Cacalia decomposita A. Gray, Pl. Wright. 2: 99. 1853. 
Type Locauiry: Mountains east of Santa Cruz, Sonora. 
Range: Southern Arizona and southwestern New Mexico to northern Mexico. 
New Mexico: San Luis Mountains ( Mearns 2219, 527, 531). 
131. CENTAUREA L. SrTar THISTLE. 
Tall, usually simple-stemmed annual with alternate, spatulate to oblong-lanceolate, 
entire or denticulate leaves and large showy heads of tubular flowers; involucre cam- 
panulate, the bracts appressed in many series, pectinate; outer corollas pink or pur- 
plish, enlarged and radiant, the inner ones ochroleucous; achenes compressed, smooth ; 
pappus of several series of unequal bristles. 
1. Centaurea americana Nutt. Journ. Acad. Phila, 2: 117, 1821. 
Plectocephalus americanus Don in Sweet, Brit. Flower Gard, 2: pl. 51, 1823-29. 
Type LocaLity: ‘On the banks of streams, and in denudated alluvial situations, 
throughout the plains or prairies of the upper part of Arkansas territory.”’ 
Range: Arkansas and Louisiana to Arizona and southward. 
New Mexico: Socorro; Mogollon Mountains; Mangas Springs; G O S Ranch; 
Mesilla; White Mountains; mountains north of Santa Rita. Moist slopes and along 
streams, in the Upper Sonoran and Transition zones. 
132. CIRSIUM Hill. Tutstte. 
Coarse biennial or perennial herbs with prickly, often pinnatifid, sessile, alternate 
leaves and large heads, the latter solitary, racemose, or clustered at the ends of the 
branches; flowers all tubular, perfect; bracts of the involucre imbricated in many 
ranks, mostly tipped with prickles; receptacle clothed with soft bristles; achenes 
oblong or obovoid, compressed, smooth; pappus of numerous plumose priaties united 
into a ring at the base, deciduous. 
KEY TO THE SPECIES. 
Bracts deep purple, reflexed for half their length, not arachnoid. 1. C. vinacewm. 
Bracts not purplish or if so only at the very tips, when reflexed 
more or less arachnoid. 
Plants acaulescent. ........-.--.--------- weceeeeee------ 2. C. acaulescens. 
Plants not acaulescent. 
At least some of the bracts pectinate-ciliate with weak 
spines; flowers greenish yellow. 
