518 COMPOSITAE (COMPOSITE FAMILY) 
ST. BARNABY’S THISTLE 
Centatirea solstitialis, L. 
Other English name: Yellow Star Thistle. 
Introduced. Annual. Propagates by seeds. 
Time of bloom: July to September. 
Seed-time: Late August to November. 
Range: Massachusetts to Ontario and Iowa, southward to the 
Carolinas and Arkansas; also common on Pacific Coast. 
Habitat: Fields, pastures, roadsides, and waste places. 
Seeds of this thistle have been noted by Alfalfa growers as a 
common impurity in Alfalfa seed, especially of states of the Ohio 
River Valley. They are so nearly the same weight of alfalfa 
/; . seed as to make removal difficult. When 
in the soil the seeds have a vitality of 
about three years, and are a most un- 
desirable acquisition. 
Stem stout, rigid, erect, fifteen to thirty 
inches tall, widely branched, gray with 
loose woolly hair, and broadly winged by 
the decurrent bases of the leaves; these 
are also gray-woolly, the lower ones pinnate 
with terminal segment large (lyrate), and 
lateral lobes narrow with wavy or sparsely 
toothed edges; upper leaves small, entire, 
nearly linear, but all strongly decurrent. 
Heads terminal, solitary, more than an 
‘inch broad, bright yellow; involucre 
broadly ovoid or nearly globular, the 
inner row of its bracts ending in shining, 
scarious tips; the intermediate row armed 
with rigid, yellow, divergent spines nearly 
an inch long, with one or two shorter 
; ones at the base; and the outermost row 
pete Sse anes having short, palmately branched spines. 
solstitialis). X }. Achenes light-colored, smooth, shining, 
with soft, white pappus much longer than the achene. (Fig. 
358.) x 
