98 COMPOSITE. CORETHROGTNE. 



genus {Heterostephiiim) in a memoir read before the American Philosophical Society, 

 we infonned him that they belonged in our opinion to L orethrogyne, notwithstand- 

 ing the want of chaiT upon the receptacle, and that they were the two doubtful 

 Asters of Hooker and Arnott, mentioned above, and one of them probably the C. 

 Califomica of DeCandoUe. Mr. Nuttall pubUshed them accordingly as species of 

 Corethrogyne, one under the name of C.incana (supposing it to be the Diplopappus 

 incanus, LinoL), the other as C. filaginifolia. Having since had the opportunity of 

 comparing original specimens of all these plants, our opinion, as regards the geiuis, 

 is fully confirmed: so perfect, indeed, is the resemblance between the C. incana, 

 Nutt. and C. Californica (excepting the chaff of the latter), that we still strongly 

 suspect they will prove to be the same species. The A . '? tomentellus, Houk. 4' Ar7i,. 

 is however a different species, perhaps too near C. filaginifolia. 



§ 1. Receptacle with linear memhranaceoxis chaffy scales intermixed among 

 the flowers, usually, if not always, wuittirig in the centre of the head. 



1. C. Califomica (DC): stems and simple branches very woolly, leafy; 

 leaves linear-lanceolate, suberect ; the lower ones lanceolate-oblong, taper- 

 ing to the base, sparingly toothed ; scales of the hemispherical involucre 

 glandular-viscid, with somewhat spreading tips; achenia densely silky- 

 villous. — DC. ! I. c. ; Hook. S^- Am. ! hot. Beechey, svppl. p. 350. 



California, Douglas! — Leaves an inch or more in lengih, acute, woolly 

 like the stem, resetnbling a Gnaphalium. Heads broad, tliree-fourihs of an 

 inch in diameter. Scales of ihe involucre rigid; the innermost linear, as 

 long as the disk, scarious below ; the exterior shorter, entirely herbaceous 

 and glandular-viscid externally, and also slightly woolly : the summit of the 

 branches likewise slightly glandular. Chali" of the receptacle narrow, sca- 

 rious, sometimes as long as the flowers and with herbaceous tips, but some of 

 them reduced to hyaline scales not more than twice the length of the achenia. 

 The achenia are densel}' clothed with very white and silky villous hairs, 

 which project beyond the summit, so as to appear like a short exterior pap- 

 pus: bristles of the jjappus unequal in size and length : the achenia of the ray 

 an abortive rudiment, with a pappus few or several, short, and very unequal 

 bristles, some of the stronger almost subulate. 



§ 2. Rccepitacle destitute of chaff. 



2. C. incana (Nutt.) : very woolly ; stem very leafy, branching above ; 

 the branches bearing 1 to 3 heads; leaves linear-lanceolate, suberect; ihe 

 lowermost oblong-lanceolate, tapering to the base, sparingly toothed ; scales 

 of the hemispherical involucre glandular-viscid, with somewhat spreading 

 tips ; the exterior lomentose ; achenia silky-canescent. — Nutt. ! in trans. Amer. 

 phil. soc. (n. ser.) 7. p. 290, excl. syn. 



St. Diego, California, Nuttall! May.— The ray-flowers (light bluish- 

 purple, Nutt.) present scarcely a trace of an ovary, and a rudimentary pap- 

 pus of only 3 or 4 very short bristles; the fertile achenia are clothed with 

 a rather shorter pubescence ; the tuft of bristly hairs which crowns the 

 branches of the style is not so strong as in the preceding species ; and there 

 are no chaffy scales on the receptacle : otherwise the two plants appear ex- 

 actly alike. It is said to exhale the heavy aromatic odor of some 

 species of Gnaphalium. — The Dij)lopappus incanus, Lindl., referred here by 

 Nuttall, is a species of Dieteria. 



3. C. filaginifolia (Nutt.) : clothed with a loose somewhat floccose and 

 deciduous wool; branches slender, rather naked above; lower leaves oblong- 

 spatulate or oblanceolate, very sharply or incisely serrate towards the afiex, 

 tapering into a short petiole; those of the branchlets lanceolate, sessile, often 

 entire, scattered ; scales of the somewhat obovoid involucre intbricated in 3 

 or 4 series, acute, somewhat appressed. membranaceous, not glandular, at 



