-250.

249c. Heads in more or less one-sided racemes --251.

249d. Heads in panicles or irregular clusters --253.

250a. Leaves rigid, linear-lanceolate =Aster, Aster ptarmicoides.=

250b. Leaves not rigid, lanceolate =Aster, Aster umbellatus.=

251a. Leaves lanceolate, sharply serrate --252.

251b. Leaves linear or narrowly linear-lanceolate, only the larger ones
with a few teeth near the middle =Aster, Aster vimineus.=

252a. Stem glabrous or somewhat pubescent
=Aster, Aster lateriflorus.=

252b. Stem woolly with long hairs
=Aster, Aster lateriflorus var. hirsuticaulis.=

253a. Bracts narrow, approximately equal in length
=Aster, Aster longifolius.=

253b. Bracts of several lengths, the outer successively shorter --254.

254a. Heads 10-15 mm. wide, including the rays
=Aster, Aster tradescanti.=

254b. Heads 15-25 mm. wide, including the rays --255.

255a. Bracts with conspicuous dilated or subrhombic tips
=Aster, Aster salicifolius.=

255b. Bracts without conspicuous green tips --256.

256a. Rays purple or rose; bog plant with linear leaves
=Aster, Aster junceus.=

256b. Rays white, or slightly tinged with blue; leaves oblong to
narrowly lanceolate =Aster, Aster paniculatus.=

GLOSSARY

=Achene.= A small, dry, hard, seed-like fruit containing a single seed.

=Acuminate.= Taper-pointed.

=Acute.= Ending with an acute angle.

=Alternate.= Located singly on the stem, with other leaves above or below.

=Annual.= Living but a single season.

=Anther.= The (usually) enlarged end of a stamen, bearing the pollen.

=Ascending.= Rising or curving obliquely upward.

=Auricle.= An ear-shape appendage at the base of a leaf or other organ.

=Auricled, auriculate.= Furnished with auricles.

=Awl-shape.= Tapering to a slender stiff point.

=Awn.= An awl-shape or bristle-shape appendage.

=Axil.= The point on a stem just above the base of a leaf or branch.

=Axillary.= Arising from or produced in the axil.

=Basal.= Arising from or produced at the base.

=Beak.= Ending in a prominent slender point.

=Bract.= A small leaf near the base of a flower or flower-stalk, or i