Part 200 (1/2)

Spikelets 1-flowered, not jointed on the pedicels. Outer glumes unequal, often bristle-pointed; the flowering glume tipped with three awns; the palet much smaller. Otherwise much as in Stipa.--Culms branching; leaves narrow, often involute. Spikelets in simple or panicled racemes or spikes. Grain linear. All grow in sterile, dry soil, and all ours have the awns naked and persistent, and flower late. (Name from _arista_, a beard or awn.)

[*] _Awns separate to the base, not jointed with the glume._

[+] _Awns very unequal; the much shorter or minute lateral ones erect, the elongated middle one horizontal or turned downward; low (5--18'

high) and branching, mostly tufted annuals, and the spikelets in nearly simple spikes._

[++] _Middle awn more or less coiled._

1. A. ramosissima, Engelm. Culms much branched; spikes loose, usually exserted; lower glumes 6--10” long, exceeding the upper, usually rather strongly 3--5-nerved; middle awn 1' long, soon abruptly hooked-recurved, the lateral ones 1--3” long.--Dry prairies of Ill., Ky., and Mo.--Also var. UNIARISTaTA, Engelm., with the lateral awns wanting.

2. A. basiramea, Engelm. Spikes closer, mostly enclosed at base, at all the lower nodes (even to the base of the culm) very short and sessile; lower glumes 4--8” long, mostly thin and 1-nerved or rather faintly 3-nerved; middle awn very slender, 6” long, the lateral 2” long.--Ill.

to Neb. and Minn.

3. A. dichotoma, Michx. (POVERTY GRa.s.s.) Culms low, very slender, much branched throughout, ascending; spikelets in narrow strict simple or compound spikes; lower glumes nearly equal (3--4” long), longer than the flowering glume and fully equalling its minute lateral awns (or unequal and shorter, in var. CURTiSSII, Gray), the soon reflexed middle awn about as long.--Dry, sandy or gravelly fields; common, Maine to Ill., and southward.

[++][++] _Middle awn nearly straight (not coiled)._

4. A. gracilis, Ell. Culms slender, erect (6--18' high), naked above and terminating in a slender raceme- or spike-like virgate panicle; lower glumes 1-nerved, about the length of the upper, the exserted lateral awns varying from one third to fully half the length of the horizontally bent middle one: or in var. DEPAUPERaTA, from one fifth to one third its length.--Sandy soil, coast of Ma.s.s., and from Ill. southward.--Middle awn 3--9” long in the ordinary forms, but not rarely shorter, and very variable often on the same plant.

[+][+] _Awns all diverging and alike, or the lateral ones moderately shorter, rarely at all coiled._

[++] _Glumes equal or the middle one longer._

5. A. stricta, Michx. Culms (2--3 high) densely tufted from a _perennial_ root, bearing a (1) long _spiked panicle_; leaves involute-thread-form, long, rigid, sometimes downy; awns about the length of the glumes (6”) or the lateral one third shorter.--Va. and southward.

6. A. oligantha, Michx. Culms (6--20' high) tufted from an _annual_ root, bearing a _loosely few-flowered raceme_; leaves short, somewhat involute when dry; lower glume 3--5-nerved (nearly 1' long); _awns capillary_, 1--3' long, much exceeding the slender spikelet.--Va. to Ill., and common southwestward.

7. A. purpurea, Nutt. Perennial; culms (1 high or less) densely tufted, spreading; leaves revolute and filiform, short; panicle loose, of rather few slender-pedicellate spikelets; lower glumes thin, 1-nerved, loose, the outer about half the length of the inner, which is 8--10” long; awns 2--4” long.--Minn. and Dak. to Tex.--Very variable.

[++][++] _Middle glume shorter than the lower; perennials, simple-stemmed, 2--4 high._

8. A. purpurascens, Poir. (Pl. 8.) _Glabrous_; leaves long, rather involute; spikelets in a (10--18') long spiked panicle; lower glumes 1-nerved; _awns much longer than the spikelet_, the middle one about 1'

long.--Ma.s.s. to Mich., Minn., and southward; common.

9. A. lanata, Poir. Tall and stout; _leaves_ tardily involute, _rough_ above, rigid; _sheaths woolly_; panicle (1--2 long) spike-like or more compound and open; glumes 1-nerved, 6--8” long; middle awn 1'

long.--Del. to Fla.

[*][*] _Awns united below into one, jointed with the apex of the glume; root annual._

10. A. tuberculsa, Nutt. Culm branched below (6--18' high), tumid at the joints; panicles rigid, loose, the branches in pairs, one of them short and about 2-flowered, the other elongated and several-flowered; lower glumes (1' long, including their slender-awned tips) longer than the upper, which is tipped with the common stalk (about its own length) of the 3 equal divergently-bent awns (1--2' long) twisting together at the base.--Sandy soil, E. Ma.s.s. to N. J.; also Wisc., Minn., and southward.

20. STPA, L. FEATHER-GRa.s.s. (Pl. 8.)

Spikelets 1-flowered, terete; the flower falling away at maturity (with the conspicuous obconical bearded and often sharp-pointed callus) from the membranaceous persistent lower glumes. Fertile glumes coriaceous, cylindrical-involute and closely embracing the smaller palet and the cylindrical grain, having a long and twisted or tortuous simple awn jointed with its apex. Stamens mostly 3. Stigmas plumose.--Perennials, with narrow involute leaves and a loose panicle. (Name from st?p?, _tow_, in allusion to the flaxen appearance of the feathery awns of the original species. In our species the awn is naked.)

[*] _Callus or base of the flower short and blunt; lower glumes pointless._

1. S. Richardsnii, Link. Culm (1--2 high) and leaves slender; panicle loose (4--5' long), with slender few-flowered branches; lower glumes nearly equal, oblong, acutish (2--4” long), about equalling the p.u.b.escent linear-oblong fertile one, which bears a tortuous awn 6--9”