542 COMPOSITAE (composite family) 



more or less bur-like, being armed over the surface with several or numerous 

 prickles or spines (the spiny free tips of the component bracts) in more than 1 

 series. Leaves mostly alternate. 



Leaves twice or thrice pinna tely dissected. 



Annuals ; . . . .' ; '. . , ,'■''.' "\ . 1« F. acanthicarpa. 



Perennials. . . . , - ■ ■ j i 



Leayes regularly pinnate, the lobes linear or narrowly oblong . 2. F. tenuifolia. 



'Leaves interruptedly pinnate, the-lobes ovate or triangular -, . ,3.fiF. ;tomentosa. 



Leav.esiflimple or simply pinnate ... . . .',, . . 4. F. Grayi,. 



1. Franseria acanthicarpa (Hook.) Coville, Contr. J5.'S. Nat.iHerb! 4':''129. 

 1903. Diffusely spreading or sometimes rather strict, 3-6 dm. or niore high, 

 from an annual or more erduring(?) root; in age scabrous or short-hirsute and 

 somewhat canes'.*'j t: leaves on long petioles, broadly ovate in outline, onc6 

 or twice pinnatilia mto short, rounded, often toothed lobes: stamiiiate racemes 

 solitary or in small panicles, the heads nodding on short slender pediincles;' 

 fruiting involucres in the axils' below, either solitary or 2 or 3 together, 1- 

 flowered, glabrous; spines flat, thin, lanceolate-subulate, with straight or 

 slightly curved but not uncinate tips. F. Hookeriana. — Cbmmon oil sandy 

 plains; throughout our range and westward to the coast. ' ' ' i- i 



2. Franseria tenuifolia Gray, PL Fendl. 80. 1848. Erect, 3-10 din. high, 

 leafy to the top, hispid, variously pubescent, or glabrate:| leaves mostly 2-3- 

 pihnately parted or dissected into narrowly oblong or Uhear lobfes, the ter- 

 minal elongated: sterile racemes commonly elongated and paniculate; fertile 

 heads in numerous glomerules below, in fruit minutely glandular, usually 

 2-fiowered, armed with 6-18 short and stout incurving spines, their tips 

 almost always hooked, and an excavated cartilaginously bordered , areola 

 above each. {Gaertneria linearis Rydb. Bull. Torr. Bot. Club 32: 133. 1905.) 

 — Kansas and Colorado to Texas and California. . ' 



3. Franseria tomentosa (Nutt.) A. Nels. Erect from perennial slender 

 creeping rootstocks, . 1-3 dm. high: leaves canescently tomentose beneath, 

 green and gl3,brate above, interruptedly pinnatifid, oblqng in outline,^ com- 

 paratively large, the lowest often 8-12 cm. long; the lobes'lisually short ahd 

 brbad: sterile racemes commonly solitary;' fruiting involucre 2-flowered,' 

 canescent, armed With I'ather 'short, coniqal-subulate, very acute, and straight 

 spines. (Ambrosia tomentosa Nutt.; F. discolor Nntt.; Gaertneria tomelito'sa 

 A. Nels. Bot. Gaz. 34: 34: 1902.) — A most ineradicable weed in cultivated 

 grouiid; Montana to New Mexicb. ' ^ 



4. Franseria Grayi A. Nels. Stems about 3 dm. high, rather stout, erect, 

 from an apparently perennial fjase, canescent with a dense sericeous Momen- 

 tum: leaves very white beneath, cinereous above,^ pinnately-' 3-5-cleft or 

 parted; the terminal division large, oblong or broadly lanceolate, serrat^; 

 upper lateral similalr but smaller; the lowest commonly very small and entire: 

 fruiting involucre 6 mm. long, 2-flowered, nearly glabrous; the short spines 

 conical-subulate, very acute, and the very tip usually uncinate-inCur^^ed. 

 (F. tomentosa Gray, PI. Fendl. 80. 1848; Gaertneria, Cmj/i A. Nels. 1. c. 35:)— , 

 Along streams; Kansas, Nebraska; and eaistern Colorado. . : r,: 



' ■ - . ' ' . - ' 'rnA .' 



44. XANTHIUM L. Cocklebur ' ' 



Coarse annual weeds with widely branching and very stout stems. .-jL^aveS; 

 alternate, toothed or lobed, petiolgd. Heads unisexual, the flowers greenish. 

 Staminate heads subglobose, in a terminal cluster; involucre of several disr 

 tinct narrow bracts in lor 2 series; receptacle cylindrical; flowers majay,, 

 separated by the bracts of the receptacle; corolla tubular. Pistillate heads 

 axillary, below the staminate; involucre closed, forming in fruit an ovoid or 

 oblong indurated bur covered with hooked prickles, 1 or 2-beaked, 2-celled, 

 each cell containing 1 seed; corolla none; pappus none; ^style 2-cleft, the 

 branches exserted through the beaks. 



1. Xanthimn echinatum Murr. Comm. Goett. 6: 32. 1783. Stem often 

 punctate with brown spots: leaves cordate or ovate, 3-ribbed. from the base. 



