I8G 



KOSACEJi:. Acama. 



21. AC-aSNA, Linn. 

 Calyx-tubo obloiiy, porsistunt, cuiilractctl uL tho throat, at leiiyth aniicil with 

 retioi-sely burhoil prickles ; limb 3 - T-partuil, vulvuto, ili!(i(huma. Petals aono. 

 8tanions 1 to 10, usually 3 to f). (Carpels 1 or 2, IVoo from thu calyx : Mtylo tor- 

 luimil : stiguia capilato ami imiltiliil : ovulo HoUtary, husihmhIoiI. Ak»>no cnchjaod 

 ill the iiidumteJ calyx, luembraiiaceous. — reronuial lierbs, often woody at the de- 

 cumbent or creeping base ; leaves nuequally pinnate, and leaflets incised or piimati- 

 tid ; llowers in crowded si)ikes or heads. 



Species about 30, belonging largely to Chili iunl Fern, and almost exelusively to the tenipeiatt! 

 and wanner regions of the southern hemisphere. There is u single Mexiean species, besides the 

 following Chilian speeies in Calilurnia. 



1. A. trifida, liuiz & Pavon. 8ilky-villous : stems erect from a wondy caudcx, 

 3 to 15 inches high: leaves mostly crowded at the base; leaflets about G pairs, 

 nearly uniform, obh>ng-(»vate, 3 to 5 lines long, pinnately cleft into 3 to 7 segments : 

 llowers green, in a cylindrical crowded spike, the lower often remote : calyxdobes 

 1^ lines long, exceeding the tube: spreading stamens jmrple ; hlaments exserted : 

 fruit ovate, 2 lines long, 3 - 4-angled ; angles armed with 2 to 4 stout prickles, and 

 shorter ones in the intervals; akene round-oblong. — Fl. ]'eruv. i. G7, t. HH. A. 

 piimati/ida, Hook. iV Arn. l)ot. Heechey, 331), not \l\\h & Pavon; Torr. iV (!ray, 

 Fl. i. m ; Torrey, ik.t. Mex. Hound, t. ID. 



Dry hills in the Coast Ranges, from Monterey to Marin Co. 



22. POTERIUM, linn. Burnet. 



Calyx-tulje turbinate, contracted at the throat, persistent, becoming 3 - 4-angled 

 or winged and thickish ; limb 4-parted, imbricate in the bud, petal-like, deciduous. 

 Petals none. Stamens 4 to 1 2 or more ; hlaments often elongated. Carpels 1 to 3, 

 free from the calyx : style terminal, filiform : stigma tufted : ovulo solitary, sus- 

 pended. Akeno enclo.sed, mendtranaceous. — Herbs, mostly i)orennial ; leaves pin- 

 nate, with coarsely tootheil petiolulate leaflets and foliaceous adnate stipules ; flowers 

 small, often polygamous or dioicious, bracteate and 2-bracteolate in a dense spike 

 upon a long naked i)eduncle. 



Species 15 or 20, of the temperate regions of the northern hemisphere. Besides the following 

 thei'e is a single sjieeies in the Atlantic States, and a second in Alaska. 



1. P. officinale, l'>enth. & Hook. Perennial, u.sually glabrous, often 2 to 4 feet 

 high : leaflets about 4 pairs, ovate to oblong, cordate at base, | to 2 inches long : 

 flowers deep purple or red, polygamous, in oblong spikes, a half to an inch long : 

 bracts often pubescent : stamens scarcely exserted : fruit a line long, equalling the 

 calyx-lobes. — Sanguisorba opcinalis, Linn. S. microcephala, Presl in Epimeliai 

 Bot. 202. 



Mendocino plains (Bohuulcr) ; Oregon {Hall) ; Alaska, Kiimicut. Fre<iuent in Europe ami 

 Northern Asia. 



2. P. annuum, Nult. Annual, glabrous, slender, (> to If) inches high : leaflets 

 4 to G pairs, ovate to oblong, half an inch long or less, (hnply pinnatilid ; segments 

 linear : flowers perfect, greenish, in ovoid to oblong heads, \ to 1 inch long : bracts 

 scarious, ovate, persistent, a line long : stamens 2 or 4, short : fruit shorter than the 

 bracts. — Hook. Fl. i. l'J8. Sanc/uisurba annua, Torr. & Gray, Fl. i. 42'J ; Torrey, 

 Marcy Pep. 285, t. 5. aS'. rnyriophylla, P>raun & Bouche, Ind. Sem. Berl. 1867, 10. 

 Poleridiuvi aiinuum, Spacli, Ann. Sci. Nat. 3 ser. v. 43. 



In the Sacramento Valley, J/nrlwaj, Bolaiidcr. Also in the valley of the Columbia, on the 

 Upper Missouri, and in the Indian Territory. 



