Hofmeisteria. COMPOSITE. 



Margacola parvula, Bnckl. in Proc. Acad. Philad. 1861, 1862. Wet wound in pni 

 Texas, Wright, Buckl, ,/, &c. (Mex., Palmr.r.) 



T. rivularis, GRAY, 1. c. Stems floating, in sliallow water rooting, and flowrriii" branches 

 ciiKTscd and ascending: leaves succulent, mostly opposite, an inch' or two in length cum 

 obovate, sparingly incised or palmately 3-lobed, contracted into a narrow connate-clasi 

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

 involucral bracts about 12, oval, obtuse : receptacle highly convex: tube of corolla slender 

 equalling the hemispherical throat and limb : style-branches flat and linear, a.-mish : prippus 

 a minute and evanescent or obscure setulose crown. In springs and streamlets, S. \V. 

 Texas, Wriijld, &c. (Adjacent Mex., Gregg, &c.) 



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

 plant of this order, probably an Ac/tillea, from a privative and y,^ s . yr^aros, 

 not waxing old, transferred by Linnaeus to an American genus.) Chiefly 

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

 corymbiform cymes or rarely paniculate; flowers blue, purple, or \vliitc. in 

 summer. --Benth. & Hook. Gen. ii. 241, excl. syn. O.ri/lnltis. Agerahnu & 

 Ccdestina, Cass., DC!. ; to which should be added Alomia, IIBK., differing only 

 in the want of pappus. 



1. EUAGERATUM. Pappus of distinct aristate or sometimes muticous palese : 

 receptacle naked. 



A. COXYZOIDKS, L. Annual, pubescent: leaves ovate or deltoid-subcordate, crenately serrate.- 

 pappus of 5 to 7 lanceolate rigid scales, mostly tapering into a scabrous awn which nearlv 

 equals the blue or white corolla, Sehk. ilandb. t. 238 ; Hook. Exot. Fl. t. 15. J . .!/, .,-,', ;i t />i,/i, 

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

 Sparingly naturalized near towns in the S. Atlantic States. (Nat. from Trop. Amcr., &,.-.) 



2. CCELESTINA. Puppus coroniform or cupulate (by the union of the paleas 

 into an entire or toothed cup or border), sometimes obsolete.-- Ccelestina, Cass., 

 DC., &c. (In our species the receptacle is naked, duration of root uncertain, 

 and flowers usually blue or violet.) 



A. COrymbosum, ZUCCAGNI. Scabrous-puberulent, erect : leaves short-petioled, ovate 



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



corolla-tube glauduliferous : pappus prominently cupulate, more or less dentate. Zurcagni 



ex Balb. in Hort. Taur. 1806; Pers. Syn. ii. 402. A. coelestinum, Sims, Bot. Mag. t. 1730; 



Lodd. Bot. Cab. t. 623. Calestina ageratoidcs, HBK. Nov. Gen. & Spec. iv. 151 ; Gray, I'l. 



Wright, ii. 70. C. ccerulea, Cass. Diet. vi. suppl. 8, t. 93. C. corymbosa, DC. 1'rn.ir. v. 108. 



New Mexico, Wright, &c. (Mex.) 

 A. littorale, GRAY. Glabrous, decumbent or assurgent : leaves rather succulent, long-pcti- 



olcd, ovate with cuneate base, serrate: corolla glabrous: pappus an extremely short crown. 



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



xvi. 78. C&lestina maritima, Torr. & Gray, Fl. ii. 64; not A<j< minm ninritiiiiitin. II15K.. 



which is a true Ageratum with diminutive pappus. Key West, S. Florida, BcnnM, I'And- 



gett, Palmer, Garber. 



8. HOFMEISTEBIA, Walp. (W. ffofmeister, SL vegetable histologist.) 

 Low suffrutcscent plants; with heads terminating slender peduncles, small 

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

 the style-branches clavate. Two species, the original one (H. fasciculata, 

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

 with 2-3-awned pappus. 



H. pluriseta, GRAY. Slightly puberulent and viscidulous, much branched : leaves with small 

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



