1206 CARDUACEAE 
49. PSILACTIS A. Gray. 
Annual caulescent herbs, glandular, pubescent or glabrate. Leaves alternate, various, 
those of the basal or lower stem-leaves with pinnatifid blades; those of the upper leaves 
often entire. Heads radiate. Involucres hemispheric: bracts in 2-3 series, wholly her- 
baceous or with herbaceous tips. Receptacle flattish. Ray-flowers pistillate in a single 
series. Disk-flowers more numerous that those of the ray, perfect. Stigmas with puberu- 
lent or hispidulous appendages. Achenes narrow, pubescent, those of the ray sometimes 
with a mere ring representing the pappus, those of the disk with a single series of short. 
hair-like bristles. 
1. Psilactis asteroides A. Gray. Stems 3-10 dm. tall, scabrous-puberulent, or 
glabrate, branching above: leaf-blades 1-7 cm. long, narrowly spatulate and toothed at 
the base of the stem, oblong or linear and entire above : involucres 3 mm. high, becoming 
rather flat at maturity ; bracts oblong to linear: ray-flowers with linear ligules 4-5 mm. 
long: achenes 2 mm. long, minutely pubescent. 
In dry soil, Texas to Arizona and adjacent Mexico. 
50. SERICOCARPUS Nees. 
Perennial caulescent herbs. Leaves alternate : blades various, entire or toothed. 
Heads radiate, in corymbs. Involucres ovoid to campanulate or cylindric, several-flow- 
ered : bracts leathery, in few series, with erect or spreading tips. Receptacle naked, pitted. 
Ray-flowers pistillate, with white or pink ligules. Disk-flowers chiefly perfect, with yel- 
lowish or purplish corollas. Anthers entire and obtuse at the base. Style-branches with 
narrow appendages. Achenes flattened, l-nerved on each side. Pappus of numerous 
scabrous bristles, the inner ones longer. 
Leaf-blades entire. 
Foliage glabrous or nearly so. 1. S. linifolius. 
Foliage manifestly pubescent. ay 
Bracts of the involucres obtuse, firm: peduncles rigid. stout. 2. S. bifoliatus. 
Braets of the involucres acute, lax : peduncles weak, slender. 8. S. acutisquamosus. 
Leaf-blades toothed. 4. S. asteroides. 
1. Sericocarpus linifdlius (L.) B.S.P. Stems often tufted, 2-7 dm. tall, glabrous 
or nearly so. Leaf-blades spatulate or linear-spatulate at the base of the stem to linear 
above, 2-6 cm. long, entire, sessile or short-petioled : involucres narrowly cylindric, 5-7 
mm. high; bracts ovate-oblong, to linear-oblong, obtuse, often with erose green tips: ray- 
flowers with linear involute ligules : pappus whitish, copious. [S. solidagineus Nees. 
In sandy soil, Canada, south to Georgia, Ohio and Louisiana. Summer and fall. 
2. Sericocarpus bifoliàtus (Walt.) Porter. Stems cinereous-pubescent, 3-7 dm. 
tall, sometimes branched below. Leaf-blades spatulate to obovate, 1-3 cm. long, obtuse or 
Sinite, vertical, sessile: involucres about 6 mm. high, cylindric ; bracts ovate to linear- 
N a obtuse, sometimes minutely pubescent : pappus white, copious. [$. tortifolius 
ees. 
In dry sandy pine lands, Virgina to Florida and Louisiana. Summer and fall. 2 i 
3. Sericocarpus acutisquamósus (Nash) Small. Similar to S. bifoliatus 1n habit, 
but less robust. Leaf-blades oblong-spatulate, 1-3.5 cm. long, rather weak, acutish or 
apiculate, entire, scabrous, sessile : involucres narrowly cylindric or cylindric-turbinate, 
6.7 mm. high ; bracts narrowly linear-lanceolate, acute, the outer ones rather densely pu- 
bescent: pappus white, copious. [S. bifoliatus acutisquamosus Nash. ] 
In pine lands, peninsular Florida. Summer. 
4. Sericocarpus asteroides (L.) B.S.P. Stems 3-8 dm. tall, glabrous at least i 
the sometimes viscid-pubescent peduncles. Leaf-blades 4-15 cm. long, toothed, those o 
the basal and lower stem-leaves spatulate, oblong or oval, those of the upper stem- 
leaves broadest at or above the middle or sometimes lanceolate : involucres 6-9 mm. 
high, cylindric or oblong-cylindric ; bracts ovate to linear, with appressed or spreading 
green tips: ray-flowers with whitish ligules 6-8 mm. long. [S. conyzoides Nees. ] 
In rocky woods, Maine to Ohio, south to Florida to Alabama. Summer. 
51. ASTER L.! 
m annual, 
Perennial branching glabrous or pubescent herbs, various in habit, but seldo 
unbranched, shrubby or spinescent. Leaves alternate: blades broad or narrow, often en- 
‘Contributed by Professor Edward S. Burgess. 
