27. Aster

L. Starwort. Aster. * Leaves, at least the lower ones, heart-shaped and petioled.

1. A. corymbo'sus, Ait. Rays 6-9, white or nearly so. Heads in corymbs. Stems slender, 1-2 feet high, zigzag. Leaves thin, smoothish, sharp-pointed, coarsely serrate, all the lower ones on slender naked petioles. - Woodlands.

2. A. macrophyl'lus, L. Rays white or bluish. Stem stout, 2-3 feet high. Leaves thickish, rough, finely serrate, the lower long-petioled. Heads in closer corymbs than in No. 1. - Woodlands.

3. A. azu'reus, Lindl. Rays 10-20, bright blue. Heads racemed or panicled. Stem roughish, erect, racemose-compound above. Leaves entire or nearly so, rough; the lower ovate-lanceolate, on long petioles; the upper lanceolate or linear, sessile. The latest flowering of our Asters. - Dry soil.

4. A. undula'tus, L. Rays bright blue. Heads racemed or panicled. Stem hoary with close pubescence, spreading. Leaves with somewhat wavy margins, entire or nearly so, ovate or ovate-lanceolate, roughish above, downy beneath; the lowest cordate, on margined petioles; the upper with winged short petioles clasping at the base, or sessile. - Dry woods.

5. A. cordifo'lius, L. Rays pale blue or nearly white. Heads small, profuse, panicled. Stem much branched. Leaves thin, sharply serrate, the lower on slender ciliate petioles. Scales of the inversely conical involucre all ap-pressed, and tipped with very short green points. - Woods and along fences.

6. A. Sagittifo'lius, Willd. Rays pale blue or purple. Heads small, in dense compound racemes or panicles. Stem smooth or nearly so, erect, with ascending branches. Leaves conspicuously serrate, ovate-lanceolate, pointed, pubescent, .the lowest on long margined petioles, the upper lanceolate or linear, pointed at both ends. Scales of the oblong involucre linear, tapering into awl-shaped, slender and loose tips. - Thickets and along fences.

7. A. Lindleya'nus, Torr, and Gr. Bays pale violet. Stem rather stout, smooth or sparsely pubescent. Leaves conspicuously serrate. Root-leaves and lowest stem-leaves ovate, more or less cordate, with margined petioles; uppermost sessile, and pointed at both ends. Heads rather small, in a loose thyrse or panicle. Scales linear, green-tipped. - Open barren grounds.

* * Upper leaves all sessile or clasping by a heart-shaped base; lower ones not heart-shaped.

8. A. laevis, L. Rays large, sky-blue. Very smooth throughout. Heads in a close panicle. Leaves lanceolate or ovate-lanceolate, chiefly entire, rough on the margins, the upper ones clasping by an auricled base. - Dry woods.

9. A. Novae-An'gliae, L. Rays many, narrow, violet-purple, showy; heads large. Involucre of many slender equal scales, apparently in a single row, clammy. Stem stout, 3-8 feet high, harry, corymbed above. Leaves very numerous, lanceolate, entire, clasping by an auricled base, pubescent. - River-banks and borders of woods.

10. A. puni'ceus, L. Rays long, lilac-blue. Scales of the involucre narrowly linear, loose, in about two rows. Stem 3-6 feet high, stout, rough-hairy, usually purple below. Leaves oblong-lanceolate, clasping by an auricled base, sparingly serrate in the middle, rough above, Smooth beneath, pointed. - Swamps; usually clustered.

11. A. tardiflo'rus, L. Rays pale violet. Stem glabrous or nearly so, 1-2 feet high. Leaves lanceolate or oblong-lanceolate, acuminate, with tapering and somewhat auricled base. Heads few, as a rule. Involucre loose, the outer scales leaf-like. - Atl. Prov.

* * * None of the leaves heart-shaped; those of the stem sessile, tapering at the base f except in No. 11 ).

12. A. rad 'ula, Ait. Rays light violet. Radical leaves all tapering into margined petioles. Stem-leaves sessile-oblong-lanceolate, pointed, sharply serrate in the middle, very rough both sides, rugose. Scales of the bell-shaped involucra oblong, appressed, with slightly spreading herbaceous tips. - Low grounds, Atl. Prov.

13. A. erieoi'des, Ait. Rays white or nearly so. Stem smooth or nearly so, 1-3 feet high, the branchlets or peduncles racemose on the upper side of the spreading branches. Lowest leaves oblong-spathulate, the others linear-lanceolate or linear-awl-shaped. - Barren soil, and' margins of lakes and rivers. Var. villosus, Torr, and Gray, has hairy stems and leaves.

14. A. multiflo'rus, Ait. Rays white, 10-20. Stem pale or hoary with minute pubescence, 1 foot high, bushy. Leaves crowded, linear, with rough margins; the upper partly clasping. Heads small, crowded on the racemose branches. Scales of the involucre with spreading green tips. - Dry soil.

15. A. Tradescan'ti, L. (A. tenuifolius.) Rays white or purplish. Scales of the involucre narrowly linear, in 3 or 4 rows. Heads small, very numerous, in 1-sided close racemes on the branches. Stem 2-4 feet high, much branched, smooth. Leaves linear lanceolate, with long slender point, the larger ones with a few remote teeth in the middle. - Low grounds.

16. A. diffu'sus, Ait. (A. miser, L.) Rays pale blue or whitish. Involucre nearly as in No. 15. Stem more or less pubescent, much branched. Heads small, in loose 1-sided racemes on the spreading branches. Leaves lanceolate, acute at each end, sharply serrate in the middle. - Low grounds.

17. A. panicula'tus, Lam. {A. simplex, Willd.) Rays pale blue or whitish. Scales of the involucre linear-awl-shaped. Stem stout, smooth or nearly so, with numerous leafy branches. Heads medium-sized, scattered, loosely paniculate. Leaves smooth, oblong to lanceolate, tapering at both ends, the lower serrate. - Moist and shady banks.

18. A. jun'ceus, Ait. Rays light purple. Stem slender, 1-3 feet high, simple, with few small heads, or loosely branching. Leaves narrow, entire, or the lower sparingly denticulate. Scales of the involucre small, narrow, in 2 or 3 rows. - Bogs and wet places.

19. A. vimin'eus, Lam. Rays white or nearly so. Stem 2-5 feet high, smooth, bushy. Leaves linear or narrowly lanceolate, the larger ones sparingly serrate in the middle with fine teeth. Heads very numerous, in 1-sided racemes on short branchlets. Scales of the involucre narrowly linear, in 3 or 4 rows. - Moist banks.

20. A. nemora'lis, Ait. Rays lilac-purple, elongated. Stem slender and leafy, the upper branches terminating in 1-flowered nearly naked peduncles. Leaves small, rigid, narrowly lanceolate, nearly entire, with revolute margins. - Swamps, Atl. Prov. and Muskoka.

21. A. ptarmicoi'des, Torr, and Gr. Rays pure white. Stems clustered, generally a foot high, each bearing a flat corymb of small heads. Leaves linear-lanceolate, acute, rigid, entire, mostly 1-nerved, with rough margins. - Dry or gravelly hills. Our earliest Aster. •22. A. acumina'tus, Michx. Rays white or faintly purple. Stem about a foot high, somewhat hairy, zigzag, panicled-corymbose at the top. Leaves large, thin, oblong-lanceolate, pointed, coarsely toothed towards the apex, entire at the base. - Cool sandy woods; mostly eastward.

23. A. umbella'tus, Mill. {Diplopappus umbellatus, Torr. and Gr.) Pappus double, the inner of long capillary bristles, the outer of short and rigid bristles. Rays white. Stem smooth, leafy to the top, tall, simple. Leaves lanceolate, long-pointed. Heads small, very numerous, in compound flat corymbs. - Moist thickets.