CAKDUACEAE 1207 



larged and cordate at the base, either entire or toothed. Rootstock usually horizontal 

 (sometimes short and erect) and bearing for several years a subterminal tuft of leaves 

 (radicals) ; these are often smaller, often larger, than the usually dissimilarly shaped 

 leaves (basal leaves) which finally encircle the base of the rising stem. Lower, middle 

 and upper cauline leaves often gradually transitional to each other in form, often of dis- 

 similar types. At the axils of the branches the subtending leaves (axiles) are gradually 

 reduced from the upper leaf-form of the stem ; but on the branches themselves the leaves 

 (rameals or bracteals) are usually profoundly modified or of a new type. Heads with both 

 tubular and radiate flowers, either coryrabed, racemed or panicled and borne on erect, 

 spreading or secund ultimate branchlets (pedicel), rarely solitary. Involucre hemi- 

 spheric, campanulate, cylindric or turbinate ; its components (bracts) imbricated in several 

 series ; the outer usually smaller or shorter than the inner, and somewhat herbaceous or 

 otherwise much modified at or toward the apex (this modified portion constituting the 

 green tip) which is itself either erect, spreading or squarrose. Receptacle flat or convex, 

 alveolate and often delicately fimbrillate. Ray -flowers pistillate, with white, pink, purple, 

 blue or violet ligules (rays). Disk-flowers perfect, consisting of a tubular base (the tube), 

 swollen above into the shape of an erect bell, urn or funnel (the bell), bearing a short five- 

 lobed spreading or erect border: disks typically yellow, usually changing to red, brown or 

 purple. Anthers obtuse and entire at the base. Stigmas flattened, their appendages subu- 

 late, lanceolate or ovate, acute. Achenes more or less flattened and nerved or ribbed, 

 either glabrous or pubescent. Pappus-bristles usually numerous, slender in one series or 

 rarely in two series, the tips of the inner ones sometimes thickened. ASTER. 



Basal and lower cauline leaves with relatively narrow blades, etc. Species Nos. 41-102. 

 Basal and lower cauline leaves with relatively broad blades, mainly of an ovate-cordate type and long- 

 petioled : upper cauline leaves essentially similar, but with shorter petioles or even sessile blades. 

 Species Nos. 1-40. 



Upper cauline leaves sessile and cordate-clasping, etc. Diversifolial Asters, Nos. 29-40. 

 Upper cauline leaves not cordate-clasping : lower petioles not dilated-clasping. 



Rays white or occasionally roseate: leaves polymorphous: no glandular hair present. White 



Biotian Asters, Nos. 1-8. 



Predominant leaves long-acuminate, their teeth very sharp : inflorescence broadly corymbose. 

 Predominant leaves incurved-acuminate, their teeth curving-backed, very salient. 



Predominant leaves ovate-lanceolate : upper axile leaves short or not greatly prolonged. 



1. A. divaricatus. 

 Predominant leaves more oblong, larger, darker ; upper axiles or 



some of them greatly prolonged. 2. A. tenebrosus. 



Predominant leaves straight-acuminate, their teeth straight-backed. 3. A. stilettiformis. 

 Predominant leaves not long-acuminate. 

 Inflorescence-clusters convex. 



Sinus (of cordated leaves) deep, enlarged : leaves oblong-lanceo- 

 late, curvescent-serrate : disk often crimson. 4. A, exccivatus. 

 Sinus usually absent : leaves ovate-lanceolate, slit-serrate : disk 



often chestnut-color. 5. A. castaneus. 



Inflorescence narrow, irregular or scanty. 



Bracts very broad and short, scale-like, chiefly green. 6. A. chlorolepis. 



Bracts narrow-linear, green tipped only. 



Sinus broad, enlarged : leaves chiefly oblong-acuminate. 7. A. Boykinii. 



Sinus sharp : leaves ovate-acute. 8. A. flexilis. 



Hays violet, purple or blue. 



Coarse radical leaves present, larger than the cauline : plants (except 



No. 13) glandular. Violet Biotian Asters. 



Plant not very rough : leaves not very thick : glandular ;hairs mi- 

 nute-tipped. 



Lower leaves serrate ; sinus deep, narrow. 9. A. multiformis. 



Lower leaves coarsely dentate; sinus shallow, broad. 10. A. riciniatus. 



Plant extremely rough : leaves very thick : glands broadly capitate. 



Sinus strongly developed : bracts neither squarrose nor slender. 11. A. macrophyllus. 

 Sinus usually absent : bracts squarrose. 



Bracts narrow, acute. 12. A. commixtus. 



Bracts broad, obtuse. 13. A. mirabilis. 



Radical leaves not large, smaller than the cauline : plants not glandu- 

 lar. Heterophyllous Asters, Nos. 14-28. 



Bracts widely squarrose, spreading or recurved. 14. A. anomalut. 



Bracts erect or appressed. 



Leaves entire or chiefly so, thick or firm. 



Involucre campanulate: bracts mainly linear, thin: leaf- 



. blades dull and scabrous above. 15. A. Shortii. 



Involucre cylindric-campanulate : bracts mainly linear-subu- 

 late, rigid : leaf-blades lustrous and smooth above. 16. A. Camptosorus. 

 Leaves serrate or otherwise toothed, at least the lower ones. 

 A. Leaves not rough, or not rough on both sides, membranous. 

 Bracts linear-obtuse or obtusish. 



Leaves smooth, firm : chief petioles winged : inflores- 

 cence narrow-racemose. 17. A. Lowrieanuf. 



