6o DAVENPORT ACADEMY OF NATURAL SCIENCES. 



+- Involucres with conspicuous or narrow scarious margins to the divisions; 

 perianth segments nearly equal. 



21. C. PUNGENS, Benth., Linn. Trans., Vol. XVII., t. 19, f. 2. 

 Spreading, 6-12 inches, more or less hoary or hispid-pubescent, sec- 

 ondary branches usually short; radical leaves oblanceolate, tapering 

 into a narrow petiole, more or less appressed, hispid-pubescent, cauHne 

 bracteate leaves opposite, smaller and cuspidate, more pungent than 

 above; involucres in somewhat condensed cymose clusters on the 

 short secondary branches; tube short (1-2 lines), triangular, costate, 

 and somewhat corrugated on the sides ; divisions unequal, more or less 

 scarious margined, shortly curved, and uncinate; flowers obconic, 

 nearly sessile; peiianth segments partly exsert, shortly cleft, oblong, 

 entire; stamens 9, partly adnate to the lower tube; styles about as 

 long as the ovary; embryo light green or yellow, with narrow cotyle- 

 dons and short radicle. 



Variety diffusa. C. diffusa, Benth., Watson, 1. c. Branches more 

 slender, naked, usually without fohaceous bracts; scarious margins to 

 the teeth of the involucre broader and more petaloid, usually light 

 pink. Santa Cruz mountains; also a smaller white form at Monterey. 



Variety cuspidata. C. cuspidata, Watson, Proc. Am. Acad., Vol. 

 XVII., p. 379. Involucres and flowers less conspicuous, with only 

 scant scarious margins to the divisions. The common form on sand- 

 ridges near San Francisco. 



After a careful study of numerous speciinens, in the field and the 

 herbarium, I am forced to the conclusion that all the above forms 

 should be included in C. puugcns, the marked variations being due 

 to differences of exposure, and not of specific value. It is somewhat 

 remarkable that the original figure of C. pimgens, in Linn. Trans., 

 should be represented with straight awns to the involucral divisions. 



-t- -t- Involucral divisions without scarious margins; perianth segments slightly 

 or conspicuously unequal. 



22. C. PRocuMBENS, Nutt., Watsou, 1. c. Slender, diffusely branched 

 from the base, 3-6 inches broad, appressed-pubescent ; radical leaves 

 narrowly lanceolate, obtuse, tapering to a slender petiole, cauline 

 bracts setaceous; involucres scattered on the lower stems, loosely 

 clustered above; tube short, turbinate-triangular; divisions 6: three 

 larger, as long as the tube, three smaller, intermediate, all recurved 

 and uncinate; flowers short pedicellate; perianth shortly exsert; seg- 



