View source for Aristida

{{Treatment/ID
|accepted_name=Aristida
|accepted_authority=L.
|publications=
|basionyms=
|synonyms=
|hierarchy=Poaceae;Poaceae subfam. Aristidoideae;Poaceae tribe Aristideae;Aristida
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Poaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Poaceae subfam. Aristidoideae]]</div><div class="higher-taxon"><small>tribe</small>[[Poaceae tribe Aristideae]]</div><div class="higher-taxon"><small>genus</small>[[Aristida]]</div></div>
|volume=Volume 25
|mention_page=
|treatment_page=page 315
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>usually perennial; herbaceous, usually cespitose, occasionally rhizomatous. <b>Culms</b> 10-150 cm, not woody, sometimes branched above the base; internodes usually pith-filled, sometimes hollow. <b>Leaves</b> sometimes predominantly basal, sometimes predominantly cauline; sheaths open; auricles lacking; ligules of hairs or very shortly membranous and long-ciliate, the 2 types generally indistinguishable. <b>Inflorescences</b> terminal, usually panicles, sometimes racemes, occasionally spikes; primary branches without axillary pulvini and usually appressed to ascending, or with axillary pulvini and ascending to strongly divergent or divaricate. <b>Spikelets</b> with 1 floret; rachillas not prolonged beyond the florets; disarticulation above the glumes. <b>Glumes</b> often longer than the florets, thin, usually 1-3-veined, acute to acuminate; florets terete or weakly laterally compressed; calluses well-developed, hirsute; lemmas fusiform, 3-veined, convolute, usually glabrous or scabridulous, usually enclosing the palea at maturity, usually with 3 terminal awns, lateral awns reduced or obsolete in some species, lemma apices sometimes narrowed to a straight or twisted beak below the awns; awns ascending to spreading, usually straight, bases sometimes twisted together into a column or the bases of the individual awns coiled, twisted, or otherwise contorted, occasionally disarticulating at maturity; paleas shorter than the lemmas, 2-veined, occasionally absent; anthers 1 or 3. <b>Caryopses</b> fusiform; hila linear, x = 11, 12.</span><!--

-->{{Treatment/Body
|distribution=Conn.;D.C;Del.;Ill.;Ind.;Mass.;Md.;Mo.;Mont.;Nebr.;N.H.;N.J.;N.Y.;Ohio;Okla.;Pa.;R.I.;Tex.;Utah;Vt.;Wyo.;Ga.;Wash.;Va.;W.Va.;Mich.;Wis.;Ariz.;Kans.;Minn.;Maine;Miss.;Tenn.;Iowa;Pacific Islands (Hawaii);Fla.;N.Mex.;Ala.;Ark.;N.C.;S.C.;La.;S.Dak.;Nev.;Puerto Rico;Colo.;Virgin Islands;Calif.;Idaho;Alta.;B.C.;Man.;Ont.;Que.;Sask.;N.Dak.;Ky.;Oreg.
|discussion=<p><i>Aristida</i> is a tropical to warm-temperate genus of 250-300 species. It grows throughout the world in dry grasslands and savannahs, sandy woodlands, arid deserts, and open, weedy habitats and on rocky slopes and mesas. All 29 species in this treatment are native to the Flora region.</p><!--
--><p>The divergent awns aid in wind and animal transportation of the florets and, by holding the florets and the caryopses they contain at an angle to the ground, in establishment. The presence of <i>Aristida</i> frequently indicates soil disturbance or abuse. Although generally poor forage grasses and, because of the calluses, potentially harmful to grazing animals, some species of <i>Aristida</i> are an important source of spring forage on western rangelands. Quail and small mammals eat small amounts of the seed.</p>
|tables=
|references={{Treatment/Reference
|id=allred1984a
|text=Allred, K.W. 1984. Morphologic variation and classification of the North American Aristida purpurea complex (Graraineae). Brittonia 36:382-395
}}{{Treatment/Reference
|id=allred1984c
|text=Allred, K.W. 1984, 1985, 1986. Studies in the genus Aristida (Gramineae) of the southeastern United States. Rhodora 86:73-77, 87:137-145, 145-155, 88:367-387
}}{{Treatment/Reference
|id=henrard1926a
|text=Henrard, J.T. 1926, 1927, 1928, 1933. A critical revision of the genus Aristida. Meded. Rijks-Herb. 54:1-701; 55G703-747
}}{{Treatment/Reference
|id=henrard1929a
|text=Henrard, J.T. 1929, 1933. A monograph of the genus Aristida. Meded. Rijks-Herb. 58:1-325
}}{{Treatment/Reference
|id=kesler2000a
|text=Kesler, T.R. 2000. A taxonomic reevaluation of Aristida striata (Poaceae) using anatomy and morphology. Master's thesis. Florida State University, Tallahassee, Florida, U.S.A. 33 pp.
}}{{Treatment/Reference
|id=peet1993a
|text=Peet, R.K. 1993. A taxonomic study of Aristida striata and A. beyricbiana. Rhodora 95:25-37
}}{{Treatment/Reference
|id=reeder1989a
|text=Reeder, J.R. and R.S. Felger. 1989. The Aristida californica-glabrata complex (Gramineae). Madrono 36:187-197
}}{{Treatment/Reference
|id=trent1990a
|text=Trent, J.S. and K.W. Allred. 1990. A taxonomic comparison of Aristida ternipes and Aristida hamulosa (Gramineae). Sida 14:251-261
}}{{Treatment/Reference
|id=vaughn1981a
|text=Vaughn, J.M. 1981. Systematics of Aristida dichotoma, basiramea, and curtissii (Poaceae). Master's thesis. University of Oklahoma, Norman, Oklahoma, U.S.A. 38 pp.
}}{{Treatment/Reference
|id=walters1994a
|text=Walters, T.E., D.S. Decker-Walters, and D.R. Gordon. 1994. Restoration considerations for wiregrass (Aristida striata): Allozymic diversity of populations. Conservation Biol. 8:581-585.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Lower glumes 3-7-veined.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Awns nearly equal, the lateral awns 8-66 mm long and at least 3/4 as long as the central awns.
|[[Aristida oligantha|Aristida oligantha]]
|-id=key-0-2
|2
|Awns markedly unequal, the lateral awns 1-4 mm long, no more than 1/2 as long as the central awns, sometimes absent.
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Plants annual; inflorescences 5-12 cm long, 2-4 cm wide
|[[Aristida ramosissima|Aristida ramosissima]]
|-id=key-0-3
|3
|Plants perennial; inflorescences 10-30 cm long, 4-26 cm wide
|[[Aristida schiedeana|Aristida schiedeana]]
|-id=key-0-1
|1
|Lower glumes 1-2(3)-veined.
|[[#key-0-2| > 2]]
|-id=key-0-4
|4
|Central awns spirally coiled at the base.
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Lateral awns 1-4 mm long, erect
|[[Aristida dichotoma|Aristida dichotoma]]
|-id=key-0-5
|5
|Lateral awns 5-13 mm long, spreading
|[[Aristida basiramea|Aristida basiramea]]
|-id=key-0-4
|4
|Central awns straight to curved, sometimes loosely contorted but not spirally coiled, at the base.
|[[#key-0-5| > 5]]
|-id=key-0-6
|6
|Lateral awns markedly reduced, usually 1/3 or less as long as the central awns.
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Panicles 1-6 cm wide, the branches erect-appressed to strongly ascending, without axillary pulvini or the pulvini only weakly developed.
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Plants annual; culms often highly branched above the base.
|[[#key-0-9| > 9]]
|-id=key-0-9
|9
|Awns flattened at the base
|[[Aristida adscensionis|Aristida adscensionis]]
|-id=key-0-9
|9
|Awns terete at the base.
|[[#key-0-10| > 10]]
|-id=key-0-10
|10
|Lemmas 2.5-10 mm long; central awns curving up to 100° at the base
|[[Aristida longespica|Aristida longespica]]
|-id=key-0-10
|10
|Lemmas 8-22 mm long; central awns with a semicircular bend at the base
|[[Aristida ramosissima|Aristida ramosissima]]
|-id=key-0-8
|8
|Plants perennial; culms rarely branched above the base.
|[[#key-0-9| > 9]]
|-id=key-0-11
|11
|Collars densely pilose, the hairs 1-3 mm, often densely tangled and deflexed; blades usually tightly involute, about 0.5 mm in diameter
|[[Aristida gypsophila|Aristida gypsophila]]
|-id=key-0-11
|11
|Collars mostly glabrous or with straight hairs, often with long hairs at the sides; blades usually flat to loosely involute, sometimes tightly involute.
|[[#key-0-12| > 12]]
|-id=key-0-12
|12
|Lateral awns absent; panicle branches spikelet-bearing to the base; plants of the Florida keys
|[[Aristida floridana|Aristida floridana]]
|-id=key-0-12
|12
|Lateral awns usually present, varying from much shorter than to equaling the central awns; panicle branches sometimes naked near the base; plants rarely found east of the Mississippi and not known at all from Florida.
|[[#key-0-13| > 13]]
|-id=key-0-13
|13
|Primary panicle branches 3-6 cm long; lateral awns (1)8-140 mm long
|[[Aristida purpurea|Aristida purpurea]]
|-id=key-0-13
|13
|Primary panicle branches 6-16 cm long; lateral awns absent or to 1(3) mm long
|[[Aristida schiedeana|Aristida schiedeana]]
|-id=key-0-7
|7
|Panicles 6-45 cm wide, at least the lower branches spreading and having well-developed axillary pulvini.
|[[#key-0-8| > 8]]
|-id=key-0-14
|14
|Lateral awns absent or no more than 3 mm long.
|[[#key-0-15| > 15]]
|-id=key-0-15
|15
|Central awns often deflexed at a sharp angle when mature; lemma apices often twisted at maturity.
|[[#key-0-16| > 16]]
|-id=key-0-16
|16
|Blades usually flat, sometimes folded, 1-2 mm wide; plants of juniper, oak, or pine woodlands
|[[Aristida schiedeana|Aristida schiedeana]]
|-id=key-0-16
|16
|Blades usually tightly involute, about 0.5 mm in diameter; plants of thorn-scrub deserts
|[[Aristida gypsophila|Aristida gypsophila]]
|-id=key-0-15
|15
|Central awns usually straight or arcuate; lemma apices not twisted.
|[[#key-0-16| > 16]]
|-id=key-0-17
|17
|Panicle branches spikelet-bearing from the base; lower glumes longer than the upper glumes
|[[Aristida floridana|Aristida floridana]]
|-id=key-0-17
|17
|Panicle branches usually naked at the base; lower glumes about equal to the upper glumes
|[[Aristida ternipes|Aristida ternipes]]
|-id=key-0-14
|14
|Lateral awns 3-23 mm long.
|[[#key-0-15| > 15]]
|-id=key-0-18
|18
|Anthers 0.8-1 mm long.
|[[#key-0-19| > 19]]
|-id=key-0-19
|19
|Spikelets usually divergent and the pedicels with axillary pulvini; secondary branches usually absent; primary branches 2-6 cm long; lemma apices with 0-2 twists when mature
|[[Aristida havardii|Aristida havardii]]
|-id=key-0-19
|19
|Spikelets usually appressed and the pedicels without axillary pulvini; secondary branches usually well-developed; primary branches 5-13 cm long; lemma apices with 4 or more twists when mature
|[[Aristida divaricata|Aristida divaricata]]
|-id=key-0-18
|18
|Anthers 1.2-3 mm long.
|[[#key-0-19| > 19]]
|-id=key-0-20
|20
|Collars glabrous or strigillose; blades with scattered hairs 1.5-3 mm long above the ligule on the adaxial surface; lower glumes about equal to or slightly shorter than the upper glumes
|[[Aristida ternipes|Aristida ternipes]]
|-id=key-0-20
|20
|Collars pubescent, with hairs 0.2-0.8 mm long; blades glabrous, sometimes scabridulous, above the ligule on the adaxial surface; lower glumes slightly longer than the upper glumes
|[[Aristida patula|Aristida patula]]
|-id=key-0-6
|6
|Lateral awns well-developed, usually at least 1/2 as long as the central awns.
|[[#key-0-7| > 7]]
|-id=key-0-21
|21
|Blades tightly involute, the adaxial surfaces densely scabrous or densely short-pubescent
|[[Aristida stricta|Aristida stricta]]
|-id=key-0-21
|21
|Blades flat or folded and lax, or, if involute, the adaxial surfaces neither densely scabrous nor densely short pubescent.
|[[#key-0-22| > 22]]
|-id=key-0-22
|22
|Rachis nodes and leaf sheaths usually lanose or floccose, sheaths occasionally glabrous
|[[Aristida lanosa|Aristida lanosa]]
|-id=key-0-22
|22
|Rachis nodes glabrous, scabrous, or with straight hairs; leaf sheaths glabrous, pilose, or floccose.
|[[#key-0-23| > 23]]
|-id=key-0-23
|23
|Junction of the lemma and awns evident; awns disarticulating at maturity.
|[[#key-0-24| > 24]]
|-id=key-0-24
|24
|Plants perennial.
|[[#key-0-25| > 25]]
|-id=key-0-25
|25
|Culms 45-100 cm tall; culms unbranched or sparingly branched; blades 12-28 cm long
|[[Aristida spiciformis|Aristida spiciformis]]
|-id=key-0-25
|25
|Culms 10-40 cm tall; culms much branched; blades usually less than 6 cm long
|[[Aristida californica|Aristida californica]]
|-id=key-0-24
|24
|Plants annual.
|[[#key-0-25| > 25]]
|-id=key-0-26
|26
|Awns divergent but not arcuate or entwined above the column; cauline internodes pubescent or glabrous
|[[Aristida californica|Aristida californica]]
|-id=key-0-26
|26
|Awns strongly arcuate, often entwined above the column or no column present; cauline internodes glabrous.
|[[#key-0-27| > 27]]
|-id=key-0-27
|27
|Glumes 10-17 mm long; lemmas beaked, the beak 2-7 mm long; awns not forming a column; calluses 1-2.5 mm long
|[[Aristida desmantha|Aristida desmantha]]
|-id=key-0-27
|27
|Glumes 20-30 mm long; lemmas not beaked; awns forming a column 8-15 mm long; calluses 3-4 mm long
|[[Aristida tuberculosa|Aristida tuberculosa]]
|-id=key-0-23
|23
|Junction of the lemma and awns not evident; awns not disarticulating at maturity. 28. Lemmas terminating in a beak 7-30 mm long; upper glumes awned, the awns 10-12 mm long
|[[Aristida spiciformis|Aristida spiciformis]]
|-id=key-0-28
|28
|Lemmas not beaked or with a beak less than 7 mm long; upper glumes unawned or with an awn to 6 mm long.
|[[#key-0-29| > 29]]
|-id=key-0-29
|29
|At least the lower primary panicle branches divergent and with axillary pulvini.
|[[#key-0-30| > 30]]
|-id=key-0-30
|30
|Lateral awns about 1/2 as thick as the central awns
|[[Aristida patula|Aristida patula]]
|-id=key-0-30
|30
|Lateral awns nearly as thick as the central awns.
|[[#key-0-31| > 31]]
|-id=key-0-31
|31
|Panicles narrow and contracted above, usually only the lower 1-2 branches spreading and with a pulvinus; lemma apices 0.2-0.3 mm wide
|[[Aristida purpurea|Aristida purpurea]]
|-id=key-0-31
|31
|Almost all panicle branches spreading and with axillary pulvini; lemma apices 0.1-0.2 mm wide.
|[[#key-0-32| > 32]]
|-id=key-0-32
|32
|Anthers 0.8-1 mm long.
|[[#key-0-33| > 33]]
|-id=key-0-33
|33
|Spikelets usually divergent and the pedicels with axillary pulvini; secondary branches absent or nearly so; primary branches 2-6 cm long; lemma apices straight or with 1 or 2 twists
|[[Aristida havardii|Aristida havardii]]
|-id=key-0-33
|33
|Spikelets usually appressed and the pedicels without axillary pulvini; secondary branches usually well-developed; primary branches 5-13 cm long; lemma apices with 4 or more twists at maturity
|[[Aristida divaricata|Aristida divaricata]]
|-id=key-0-32
|32
|Anthers 1-3 mm long.
|[[#key-0-33| > 33]]
|-id=key-0-34
|34
|Base of the blades with scattered hairs 1.5-3 mm long on the adaxial surfaces
|[[Aristida ternipes|Aristida ternipes]]
|-id=key-0-34
|34
|Base of the blades glabrous or puberulent on the adaxial surface, the hairs, if present, less than 0.5 mm long.
|[[#key-0-35| > 35]]
|-id=key-0-35
|35
|Glumes reddish, the lower glumes often shorter than the upper glumes; awns ascending to divaricate, (8)13-140 mm long; terminal spikelets usually appressed and without axillary pulvini
|[[Aristida purpurea|Aristida purpurea]]
|-id=key-0-35
|35
|Glumes brownish, equal or unequal; awns spreading to horizontal, 5-15 mm long; terminal spikelets often spreading from axillary pulvini
|[[Aristida pansa|Aristida pansa]]
|-id=key-0-29
|29
|Lower primary panicle branches (pedicels in racemose species) appressed, without axillary pulvini.
|[[#key-0-30| > 30]]
|-id=key-0-36
|36
|Plants with well-developed rhizomes; basal sheaths shredding into threadlike segments at maturity
|[[Aristida rhizomopbora|Aristida rhizomopbora]]
|-id=key-0-36
|36
|Plants tufted, without rhizomes; basal sheaths not fibrous, not shredding into threadlike segments even when old.
|[[#key-0-37| > 37]]
|-id=key-0-37
|37
|Lower inflorescence nodes with only 1 spikelet; inflorescences spicate or racemose
|[[Aristida mobrii|Aristida mobrii]]
|-id=key-0-37
|37
|Lower inflorescence nodes with 2 or more spikelets; inflorescences racemose or paniculate.
|[[#key-0-38| > 38]]
|-id=key-0-38
|38
|Lower glumes usually 1/3– 3/4 as long as the upper glumes.
|[[#key-0-39| > 39]]
|-id=key-0-39
|39
|Plants annual
|[[Aristida adscensionis|Aristida adscensionis]]
|-id=key-0-39
|39
|Plants perennial.
|[[#key-0-40| > 40]]
|-id=key-0-40
|40
|Lemma awns 8-15 mm long; lemmas 5-7 mm long
|[[Aristida gyrans|Aristida gyrans]]
|-id=key-0-40
|40
|Lemma awns (8)15-140 mm long; lemmas 6-16 mm long
|[[Aristida purpurea|Aristida purpurea]]
|-id=key-0-38
|38
|Lower glumes usually more than 3/4 as long as the upper glumes.
|[[#key-0-39| > 39]]
|-id=key-0-41
|41
|Plants annual.
|[[#key-0-42| > 42]]
|-id=key-0-42
|42
|Awns flat at the base
|[[Aristida adscensionis|Aristida adscensionis]]
|-id=key-0-42
|42
|Awns terete at the base
|[[Aristida longespica|Aristida longespica]]
|-id=key-0-41
|41
|Plants perennial.
|[[#key-0-42| > 42]]
|-id=key-0-43
|43
|Lemma apices prominently twisted for 3-6 mm; blades usually curled at maturity; leaves forming a basal tuft
|[[Aristida arizonica|Aristida arizonica]]
|-id=key-0-43
|43
|Lemma apices straight or only slightly twisted; blades usually not curled at maturity; leaves variously distributed.
|[[#key-0-44| > 44]]
|-id=key-0-44
|44
|Lower glumes prominently 2-keeled, (7.5)9-13 mm long; central awns 15-40 mm long
|[[Aristida palustris|Aristida palustris]]
|-id=key-0-44
|44
|Lower glumes usually 1-keeled, if 2-keeled, 5-9 mm long; central awns 8-25 mm long, [revert to left]
|[[#key-0-45| > 45]]
|-id=key-0-45
|45
|Central awns about twice as thick as the lateral awns, divergent to arcuate-reflexed.
|[[#key-0-46| > 46]]
|-id=key-0-46
|46
|All 3 awns divergent to reflexed and contorted at the base; lower rachis nodes usually associated with 2 spikelets (occasionally 1 or 3), 1 pedicellate and 1 sessile
|[[Aristida simpliciflora|Aristida simpliciflora]]
|-id=key-0-46
|46
|Lateral awns usually erect to ascending and not contorted at the base; lower rachis nodes usually associated with more than 2 spikelets, pedicellate to subsessile
|[[Aristida purpurascens|Aristida purpurascens]]
|-id=key-0-45
|45
|Central awns about the same thickness as the lateral awns, erect to spreading.
|[[#key-0-46| > 46]]
|-id=key-0-47
|47
|Lower glumes 1-4 mm longer than the upper glumes
|[[Aristida purpurascens|Aristida purpurascens]]
|-id=key-0-47
|47
|Lower glumes from shorter than to 1 mm longer than the upper glumes.
|[[#key-0-48| > 48]]
|-id=key-0-48
|48
|Culms usually 3-6 mm thick at the base; primary panicle branches 4-20 cm long; lower glumes 1-veined
|[[Aristida condensata|Aristida condensata]]
|-id=key-0-48
|48
|Culms usually 1-4 mm thick at the base; primary panicle branches 1-5 cm long; lower glumes 1-2-veined.
|[[#key-0-49| > 49]]
|-id=key-0-49
|49
|Calluses 0.4-0.8 mm long
|[[Aristida purpurascens|Aristida purpurascens]]
|-id=key-0-49
|49
|Calluses 1-2 mm long
|[[Aristida gyrans|Aristida gyrans]]
|}
</div></div><!--

-->{{#Taxon:
name=Aristida
|author=Kelly W. Allred;
|authority=L.
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Poaceae
|distribution=Conn.;D.C;Del.;Ill.;Ind.;Mass.;Md.;Mo.;Mont.;Nebr.;N.H.;N.J.;N.Y.;Ohio;Okla.;Pa.;R.I.;Tex.;Utah;Vt.;Wyo.;Ga.;Wash.;Va.;W.Va.;Mich.;Wis.;Ariz.;Kans.;Minn.;Maine;Miss.;Tenn.;Iowa;Pacific Islands (Hawaii);Fla.;N.Mex.;Ala.;Ark.;N.C.;S.C.;La.;S.Dak.;Nev.;Puerto Rico;Colo.;Virgin Islands;Calif.;Idaho;Alta.;B.C.;Man.;Ont.;Que.;Sask.;N.Dak.;Ky.;Oreg.
|reference=allred1984a;allred1984c;henrard1926a;henrard1929a;kesler2000a;peet1993a;reeder1989a;trent1990a;vaughn1981a;walters1994a
|publication title=
|publication year=
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V25/V25_983.xml
|subfamily=Poaceae subfam. Aristidoideae
|tribe=Poaceae tribe Aristideae
|genus=Aristida
}}<!--

-->[[Category:Treatment]][[Category:Poaceae tribe Aristideae]]