Sofmeisterta. CCOIPOSITJi;. (jg 



Margacola parvula, Buckl. in Proc. Acad. Philad. 1861, 1862. — Wet ground in prairies 

 Texas, Wright, Buckley, ic. (Mex., Palmer.) 

 T. rivTllaris, Gray, 1. c. St.ni^ floating, in shallow water rooting, and flowering branches 

 emersed and asn-uding: leaves .-iicculent, mostly opposite, an inch or two in leugtli, cuneate- 

 obovate, sjiariugly incised or palmately .3-lolied, contracted into a narrow connate-claff.iug 

 auriculate base : heads fewer or solitary on simple peduncles, 3 or 4 lines in diameter : 

 iuTolucral bracts about 1 2. oval, obtuse : receptacle highly convex : tube of corolla slender, 

 equalling the hemispherical throat and limb : style-branches flat and linear, atutish: j.:i].;:us 

 a minute and evanescent or obscure si-tulose crown. — In springs and streamlets, S. AV. 

 Texas, II'/v'(7/i(, &c. (Ailjacent Mex , Gca/j, &c.) 



7. AG-ERATUM, L. (Ancient Greek and Latin name of .some aromatic 

 plant of this order, probably an Achillea, from a privative and y)?pas, y/paro^. 

 not wasinu old, transferred by Linnaeus to an American "enus.) — C hiefly 

 tropical, herbaceous, and with opposite petiolate leaves ; heads small in terminal 

 corymbiform cymes or rarely paniculate; flowers blue, purple, or white, in 

 summer. — Benth. & Hook. Gen. ii. 241, excl. syn. Oxylohus. Ageratum i: 

 Ccehstiua. Cass., DC. ; to which should be added Ahmia, HBK., differing only 

 in the want of pappus. 



§ 1. EuAGEEATUM. Pappus of distinct aristate or sometimes muticous palese : 

 receptacle naked. 



A. cos-TzoiDES, L. Annual, pubescent: leaves ovate or deltciij-subcordate, creuately serrate: 

 pappus of 5 to 7 lanceolate rigid scales, mostly tapering into a scabrous ami which nearly 

 equals the blue or white corolla. — Schk. Handb. t. 23S : Hook. Exot. Fl. t. 15. A. ilfxicanum, 

 Sims, Bot. JIag. t. 2524, &c., a more pubescent form, common in ornamental cultivation. — 

 .Sparingly naturalized near towns in tlie .S. Atlantic States. (Sat. from Trop. Amer., &c.) 



§ 2. CcELESTiXA. Pappus coroniform or cupulate (by the union of the paleae 

 into an entire or toothed cup or borderl. sometimes obsolete. — C'celesdna. Cass., 

 DC, <fcc. I In our species the receptacle is naked, duration of root uncertain, 

 and flowers usually blue or violet.) 



A. corymbosuill, Zuccagxi. Scabrous-pubemlent, erect : leaves .short-petioled, ovate 

 to oblong-lanceolate, irregularly few-several-toothed : floriferous branches naked above : 

 eoroUa-tube glauduliferous : pappus prominently cupulate, more or less dentate. — Zuccagni 

 ex Balb. in Hort. Taur. 1806; Pers. Syu, ii. 402. A. calestinum, Sims. Bot. IMag. t 1730; 

 Lodd. Bot. Cab. t. 623. Cakstina ageratoides, HBK. Nov. Gen. & Sjiec. iv. 151 ; Gray, PI. 

 Wright, ii. 70. C. ccerulea, Cass. Diet. vi. suppl. S. t. 93. '.'. corymhosa, DC. Prodr. v. 108. 

 — Xew Mexico, Wright, &.C. (^Mex.) 

 -A. littorale, Gray. Glala-ous. decumbent or assurgent: leaves rather succulent, long-peti- 

 oled, ovate with cuneate base, serrate : corolla glalruu? : pappus an extremely short crown, 

 with or without several minute narrow teeth, or reduced to a mere ring. — Proc. Am. Acad. 

 xvi. 78. — Ccehstiua maritima, Torr. & Gray, PI. ii. 64; not Aneratiim maritimum, HBK., 

 which is a true Ageratum with diminutive pappus. — Key West, .S. Florida, Bennett, Blod- 

 gett, Palmer, Garher. 



8. HOFMEISTltlRIA, Walp. (IT. -ffb/)?zeiVer, a vegetable histologist.) 

 — Low suffrutescent plants ; with heads terminating slender peduncles, small 

 incised leaves either opposite or alternate on long petioles, and whitish flowers : 

 the stvle-branches clavate. — Two species, the original one (H. faicicvlota. 

 "Walp. Rep. vi. 106 ; Helogyne, Benth. Bot. Sulph. 20, t. 14), of Lower California, 

 with 2— 3-awned pappus. 



H. pluriseta, Gray. SH ghtly pnberulent and viscidulous, much branched : leaves with small 

 (2 to 5 lines long) deltoid to obloDg blade very much shorter than the petiole : heads about 



