546 COMPOSITAE 
= Centaurea preen Thuill. Protean Knapweed. Fig. 5946. 
Cent Thuill. Fl. Paris “nk 2.4 1799, 
yee nigra var. radiata DC. Fl. Fra ae ak 1815. 
lants similar to C. jacea; ‘ieoloo broadly elliptic or subglobose, about 1.5 cm. long and 
as wide or wider, the appendag es - the 1 Renan — o dark brown, roundish with broad, 
pectinately frin nge ed margins, the laciniae filifor Deas anaiadsees more or less setulose, 
ut as lon ad i the width of the essere of the Hote hue the appendages completely covering the 
base of ox le phyllaries; marginal flowers with radiately vp orollas, sterile; pappus 
mere peseesentl by a few or numerous unequal paleae, mostly 0.5 mm. long or less, rarely 
obso 
* por and roadsides, widespread and common particularly at lower elevations west of the Cascade Mountain 
Washington to northwestern California: British Columbia; eastern United States. Cultivated around Raters, 
may account for i “Pie — yaa it is  hercrees specific recognition because in our area it is by far the most 
0 e 
Y= 2 S This plant, introduced. from Europe, is generally regarded as a hybrid of C, age and C, nigra, a fact which 
t 
‘ 
& 
9. Centaurea nigra L. Black Knapweed. Fig. 5947. 
Centaurea nigra L. Sp. Pl. 911. 
Centaurea jacea var. nigra Briq. in Heal. Fl. Mitt.-Eur. 6: 954. 1929. 
similar to C. jacea; involucre roundish-cupshaped, about 1.5 cm. long and as wide as 
a - 
Occa oo in weedy places and in fields; i ea and northwestern Oregon; adventive in central Cali- 
fornia; caters United States. Introduced from Europe. J canes pt. 
10. Copetete nigréscens Willd. Short-fringed Knapweed. Fig. 5948. 
Centaurea pratbeage oto d. Sp. Pl. 3: 2288. 1804. 
Centaurea dubia Suter, Fl. Helvet. 2: 202. 1802. Not Gmelin. 
Plants ari to C. jacea; cauline leaves lanceolate, oe Sate at base, sessile; involucre 
broadly oblong or cylindric, longer than broad, about 1.5 cm. lon , the appendages of t the phy 1- 
laries smaller, not covering the greenish or straw-colored Sosea. ‘triangular, pectinate-fringed, 
h t i ile margina 
the segments a the width of the undivided part of the phyllaries; sterile mar | 
flowers generally present and radiately aia pappus reduced to sma ne. 
Widespread but rather rare, ruderal - font ral; Washington and northern Oregon; Idaho; eastern United 
States. Introduced from Europe. June—Sep 
11. Centaurea meliténsis L. Napa Thistle or Tocalote. Fig. 5949. 
t itensis L. Sp. Pl. 917. 1783. 
and 
leaves sessile and decurrent, narrowly oblong or oblong-oblanceolate, up to 5 cm. long a 
e, margin entire or gen eeatly: more or less dentate, the u ec leaves small but not 
ut 1.5 cm. s 
te) ong 
triangular, LHe gs ap) eons e; flowers yellow, numerous, the outermost with filiform lobes 
and inconspicuous ; ac 75 mm. lo ong, light es or buff, ‘all ith pappus ; pappus- bristles to 
: mm. long, slen E sof 
British Columbia, Washington, northern Oregon, and Lower Cali fornia; occasional east to the pec 2d coast; 
Hawaiian otra South America; South Africa; Australia. Native in the Mediterranean region. April-Sept. 
12. Centaurea solstitialis L. Barnaby’s Thistle or Yellow Star-thistle. Fig. 5950. 
Centaurea solstitialis L. Sp. Pl. 917. 1753. 
Plants annual, es arachnoid-tomentose and scabrid, generally 3-10 dm. tall; stems erect, 
openly branched from near the base, the branches stiff and somewhat sal leave winged by the de- 
ti Ss! id. 6 
t 
shorter than the blade, the cauline i“ sessile and decurren t, line near i it. nae Me as muc 
5 
_as 10 cm. long and 5 mm. wide near the base but much johcces and even scale-like on the uppermost 
