252 COMPOSITES. (COMPOSITE FAMILY.) 



1. X. Strumkrium, L. ( COMMON COCKLEBUR.) Rough; stems unarmed; 

 leaves dilated-triangular and more or less heart-shaped, on long petioles, toothed and 

 cut or obscurely lobed; fruit oval or oblong ('-' long), pubescent on the 

 lower part of and between the hooked prickles, and with two strong and usually 

 straight beaks at the summit. Barn-yards, &c. (Nat. from Eu.) Varies into 

 forms with more spotted stems, and often larger fruit (f- 1' long), which is 

 either glabrous, glandular, or glandular-hairy, the prickles longer and the beaks 

 often incurved. (X. Canadense, Mill., c.) River-banks, &c., common west- 

 ward ; apparently indigenous. And this passes into 



Var. echinktum. {X. echinatum, Murr., &c.) Fruit turgid (!' long), 

 thickly clothed with long prickles, glandular-hispid, the beaks commonly in- 

 curved. Sandy sea-shore, and along the Great Lakes and rivers. Perhaps 

 an immigrant from farther south. Now widely scattered over the warmer parts 

 of the world. 



2. X. SPINOSUM, L. (SPINY CLOTBUR.) Hoary-pubescent ; stems slender, 

 with slender yellow 3-parted spines at the base of the lanceolate or ovate-lanceolate 

 leaves; these taper into a short petiole, are white-downy beneath, often 2- 

 3-lobed or cut; fruit (J' long) pointed with a single short beak. Waste places 

 on the sea-board and along rivers, southward. (Nat. from Trop. Amer. ?) 



% 

 32. TETRAGONOTHECA, Dill. TETRAGONOTHECA. 



Heads many-flowered, radiate ; the rays 6-9, fertile. Involucre double ; the 

 outer of 4 large and leafy ovate scales, which are united below by their margins 

 into a 4-angled or winged cup ; the inner of as many small and chaffy scales as 

 there are ray-flowers, and partly clasping their achenia. Receptacle convex or 

 conical, with narrow and membranaceous chaff between the flowers. Achenia 

 roundish and obovoid, flat at the top. Pappus none. An erect perennial herb, 

 viscidly hairy when young, with opposite and coarsely toothed oval or oblong 

 leaves, their sessile bases sometimes connate, and large single heads of pale yel- 

 low flowers, on terminal peduncles. (Name compounded of rerpaywfos, four- 

 angled, and 0f)KT], a case, from the shape of the involucre.) 



1. T. helianthoides, L. Sandy soil, Virginia and southward. June. 



33. ECLiPTA, L. ECLIPTA. 



Heads many-flowered, radiate ; the rays short, fertile ; the disk-flowers perfect, 

 4-toothed. Scales of the involucre 10- 12, in 2 rows, leaf-like, ovate-lanceolate. 

 Receptacle flat, with almost bristle-form chaff between the flowers. Achenia 

 short, 3 - 4-sided, or in the disk laterally flattened, roughened on the sides, hairy 

 at the summit; the pappus none, or an obscure denticulate crown. Annual 

 or biennial rough herbs, with slender stems and opposite lanceolate or oblong 

 leaves. Heads solitary, small. Flowers whitish : anthers brown. (Name from 

 cKXetVo), to be deficient, alluding to the absence of pappus.) 



1. E. procumbens, Michx. Rough with close appressed hairs; stems 

 procumbent, creeping, or ascending ; leaves oblong'lanceolate, acute at each end, 

 sessile, slightly serrate ; peduncles many times longer than the head. Var. 

 BRACHYPODA has the peduncles not more than twice the length of the heads. 



