A NEW STIPA (POACEAE: STIPEAE) FROM IDAHO AND NEVADA

7 Pages·1998·5.1 MB·English

by  Michael Curto

Madrono, Vol. 45, No. 1, pp. 57-63, 1998
A NEW STIPA (POACEAE: STIPEAE) FROM IDAHO AND NEVADA
Michael Curto
Biology Department, Utah State University Logan, UT 84322-5305
Douglass M. Henderson
1
Department of Biological Sciences, University of Idaho Moscow, ID 83843
Abstract
Stipa shoshoneana is a new grass species principally from east-central Idaho, but with a disjunct
population in the Belted Range ofsouthern Nevada. Stipa shoshoneana is allied with Eurasian species of
Stipa L. sect. Lasiagrostis (Link) Hackel, and with North American stipoids historically assigned to
Orvzopsis sensu amplo. Vegetative features, panicles, glumes, anthoecia, and flowers approximate Stipa
canadensis Poir., but the lemma callus and awn morphology resemble Orvzopsis pungens (Torr.) A.S.
Hitchc.
Introduction the undescribed species. Oryzopsis exigua Thurber
During 1978, three grass specimens were col- is present at several sites across the Salmon River
Mountains and Lemhi Range, but has not been
lected (D. M. Henderson 4432) within the Salmon
found with the undescribed species.
River Canyon ofLemhi County, Idaho, that possess
Twelve other stipoids occur within the geograph-
a unique combination of micro- and macromor-
ical extent ofthe undescribed species: Stipa comata
phological character-states, but with clear alliance Trin. & Rupr. (=Hesperostipa comata [Trin. &
to Eurasian species of Stipa L. sect. Lasiagrostis
s(tLriinckto)),Haancdketlo a(g=rAocuhpnaofthNeorrutmh APm.erBiecaaunv.stispeonisdus Riudpurl.a][TBrairnk.]woBratrhk)w;orS.thv)i;riSd.ulhaymTreinno.i(d=eNsasRs.e&llaS.v;irS.-
historically assigned to Oryzopsis sensu amplo. lettermanii Vasey; S. nelsonii Scribn.; S. nevadensis
Vegetative features, spikelet arrangement, glumes, B. L. Johnson; S. occidentalis Thurber; S. pineto-
anthoecia (lemma and palea without callus or awn) rum M. E. Jones; S. richardsonii Link; S. thurber-
and flowers approximate Stipa canadensis Poir. iana Piper; S. webberi (Thurber) B. L&. Johnson; and
Oryzopsis swallenii C. L. Hitchcock Spellenberg.
(=Oryzopsis canadensis [Poir.] Torr.), but the lem-
ma callus and awn parallel Oryzopsis pungens Note that the last ten species were all recombined
in Achnatherum by Barkworth (1993). The unde-
(Torr.) A. S. Hitchc.
Over 200 subsequently collected specimens of scribed species is, however, ecologically segregated
this enigmatic grass confirmed the presence of from all twelve, as it occurs only on or at the base
more than just a few anomalous plants. Fourteen ofnear-vertical cliffs not occupied by any other sti-
widely separated populations are known within the poid.
Although these populations from east-central
Salmon River Mountains and Lemhi Range ofeast-
Idaho and southcentral Nevada constitute a previ-
central Idaho, and a small disjunct population exists
in the Belted Range of southcentral Nevada. ously undescribed species, ready assignment to
The known geographical range of this unde- Oryzopsis is now incongruous with recent generic
scribed species occurs beyond the spatial extent of realignments in the American Stipeae (Barkworth
1983, 1990, 1993; Barkworth and Everett 1987)
any close tribal relative. Stipa canadensis and Ory-
zopsis pungens, both species of Canada and the that 1) excluded Stipa L. from North and South
northeastern United States, are presently unknown America; 2) treated Oryzopsis as a unispecific ge-
nus comprising only O. asperifolia Michx.; 3) reas-
within Idaho, although both occur nearby in south-
ern British Columbia and Alberta. Oryzopsis mi- signed several North American Oryzopsis to other
cranthum (Trin. & Rupr.) Thurber {=Piptatherum genera; and 4) temporarily retained S. canadensis,
micranthum [Trin. & Rupr.] Barkworth) is locally O. exigua, and O. pungens in Oryzopsis as an in-
frequent to common throughout the Great Basin, formally recognized group, "Boreobtusae", with
central Rocky Mountains, and northern Great uncertain generic affinity. Anthoecial morphology
Plains, but is known within Idaho from only one and lemma epidermal cell patterns expressed by the
site in southwestern Clark County (Moseley and "Boreobtusae" are traceable to Miocene stipoids of
Henderson 1994) ca. 30 km by air northeast across preFsoerntt-hdeaypaNstebdreacsakdea,(wTehohmaavsesodnela19y8e0d).the formal
Birch Creek Valley from the closest population of
naming of this new species while these generic re-
alignments have transpired. Without question, Sti-
1 Deceased 1996. During 1993 and 1994, Henderson peae systematics are very complex and likely in-
participated in the writing and editing of previous drafts. volve reticulate evolution among ancestral ge-
i
MADRONO
58 [Vol. 45
nomes, as first discussed by Johnson (1945, 1972).
The recognition of Oryzopsis sensu amplo has long
been problematic owing to the obvious heteroge-
neity within the genus, and to the lack ofconsistent
macromorphological difference from Stipa sensu
amplo (Johnson 1945, 1972; Hoover 1966; Hitch-
cock and Spellenberg 1968; Spellenberg and Meh-
lenbacher 1971; Maze 1972; Kam and Maze 1974;
Freitag 1975, 1985; Barkworth and Everett 1987).
While it is clear that the North American "Boreob-
tusae" are only partially similar in macromorphol-
ogy to O. asperifolia, an alternative generic group-
tinugsaeis"naortermeaacdriloymoervpihdoelnto,giacsalslpyecdiiesssiomfila"rB.oreob- c&' a("Jo!sc* o £ -a
o a o
Obvious qualitative differences in floral, spikelet, u C
o
asspcnerdciibveeesdgestopaeftciie"vseB.ormBeooortbphthuoOs.laoepg,uy"ngeeixnniscstlu(ad2im«n=og2n2gt,hetJhoehunnfsdooeun-r c££ 3BO°h.z.^a0bl0'-*o<>53D 2£X «6x
l1e9n4b5e)rgand196O8.)exsihgaurae (w2int=h22O,. Haistpecrhicfooclkiaan(d2/7S=p4e6l,- ^2o} sau -^aa a v £*a ao 03 - OX)
Johnson 1945; 2/2=48, Bowden 1960) the combi- c/5 S CO CM
nation of a fused style column bearing two or three
-o
stigmata, together with obovate glumes both shorter CcD o ca
than or equal to the lemma body apex and divari- o '3. <D
Cd
cate at fruit dissemination. However, the florets of (N Lov
£
O. pungens and O. exigua differ markedly from c in
each other (Table 1). Both S. canadensis and the ri imall ;xsert On 960;
undescribed species have free styles along with el- mI pX C CO
a On
latihnpedticnfalolonr-egdtlisvuamorefiscSa.ltoecnaagtnerafrduteihntasdniisstsheaemnidlneattmhimeoan.unbBdouedtsycargaiapbieenxd, O 2s£<u ie£n =g3 O3 cd a-od ilaplatae hnoso wCdoQer Lu>o
species are otherwise dissimilar (Table 1). ri CM
To better evaluate taxonomic placement of both
the enigmatic "Boreobtusae" and the undescribed c S c
pspoeucsieesd,bwyeBarrekawssoerstshedantdheEvceernettrtal(1a9r8g7u)mefnotr gees-- 1) cg A £ Te3d
neric monophyly as based on putatively autapo- o£ — ts in
morphic lemma epidermal cell patterns first dis- .2 £ ri hoi 0>
cussed by Thomasson (1976, 1978a). mI OC3JJ 6<v oc rO-
o a- O cI/) ON
Methods t> plum (Joh
free ally berg
Laminar, lemmatal, and paleal abaxial epidermal J o s c4 rri)
patterns were observed from material prepared fol-
lowing the sodium hydroxide/chlorozol black clear-
ing/staining method detailed by Thomasson lat<
mm d
(1978b). Descriptions of all laminar and lemmatal
preparations follow Ellis (1976, 1979). Embryos ri no serte
were dissected from mature fruits first immersed in in s: X
<u
bwlmeoiefinrtlaeittnoemgdacowdooaenlteuforipvloetrernrenimprgooahopvttee.-rdtiMipifnstrporoetemtirmciaocdvihhesordhtoefsmp,rlooasptmroeemftraeruneiadcttsoeutgdnheterisn-n r*.i n"i4cc3di Ion f.rpe£< p<O£luu oHpa
distilled water vials kept on ice for 48 hours, and J o ri ri ri
subsequently fixed/stained in aceto-orcein. Meiotic
counts were obtained from anthers fixed in 3:1 eth- <L) O
anol acetic acid and stained in aceto-carmine. Ob- 5£ die
:
servations and drawings were made through aZeiss
Standard 18 microscope with a camera-lucida at-
tachment. Voucher specimens for chromosome
counts are deposited at CAS. cu < J
1998] CURTO AND HENDERSON: A NEW STIPA 59
Forour morphometric comparisons among "Bor- thoecia, et flores habet, sed differt callis lemmatum
eobtusae" species, we examined and measured 204 brevibus, aristis curtis caducis, antheris penicillatis,
specimens of the undescribed species, 64 speci- et chromosomatum numero aequante 20.
mens of O. exigua at ID, IDS, and UTC, and 470 Plants rhizocarpic, iteroparous perennials. Culms
specimens ofother "Boreobtusae" (76 S. canaden- herbaceous, 20-50 cm tall, densely tufted, slender,
sis, 157 O. micrantha, and 237 O. pungens), bor- geniculate or ascending to erect; unbranched dis-
rowed from CAN, MIN, and RM. tally; nodes 2-3, glabrate, internodes hollow, an-
trorsely scabridulous; innovations intravaginal.
Results and Discussion Leaves mostly basal, few cauline; vernation con-
A discussion of generic relationships and rea- volute. Sheaths exauriculate; margins free; cross-
section rounded; transverse septae absent; abaxial
lignments will be presented in another paper. In surface scabridulous. Ligules adaxial; membranous
brief, we conclude that the undescribed species and throughout; 1.8-5.5 mm long, apex acute, often lac-
S. canadensis are probably best placed with species erate. Lamina narrowly elongate, the length width
po{fl^aAccSethminepanatthoLe.fruOm.secPe.tx.iBgeuLaaausvai.nadgsreOon.sstupiussntgrie(cnLtsoi),n.kw)AesHrfaeocrmkateihlne rsactaibori>dul3o0:u1s;aplloanngarveoirnsinavonldutmearwgiitnhs.drSyyinnfgl,:orsetsifcf-,
ences terminal, ebracteate or with a solitary linear
at an impasse. Ifboth are transferred to Stipa or to bract at the proximal nodes; paniculate, ultimately
Achnatherum, then either genus would incorporate
diffuse, rachis and branches persistent; rachis nodes
species combining fused styles and short glumes, 3-7; rachis 33-220 mm long; most-proximal rachis
making the exclusion of O. asperifolia, the gener- mm
internode 0.5-63.0 long; branches persistent,
itype of Oryzopsis, even less-tenable. Perhaps both
O. exigua and O. pungens should remain in Ory- terminating at spikelets, slender to subcapillary, ir-
regularly quadrangular, scabridulous; primary
zopsis despite their incongruities otherwise with O.
branches l-2(-4) per node, most-proximal primary
asperifolia. branches 18-116 mm long, distance to initial sec-
Achnatherum sensu stricto, the greatly enlarged ondary branch 4-76 mm long; reflexed 90°-270°,
and heterogeneous Achnatherum sensu Barkworth
bearing axillary pulvini; secondary and tertiary
(1993), and the newly recognized Australian seg-
& branching strictly dichotomous, branches bearing
regate genusAustrostipa S.W.L. Jacobs J. Everett axillary pulvini and divaricate pre- and post-anthe-
(1996), form a macromorphological continuum
sis; penultimate and ultimate branches adpressed.
with Stipa; and are not globally circumscribable
Spikelets borne as distinctly pedicellate monads,
Linnean genera with any greater coherence or pre-
dictive utility than Stipa sensu amplo. Although a3.d3p-r5e.s3semdminlfornugit;exfcllouredtisnganldemfmloawearwsn;1,prbei-saenxtuhael-;
others may emphasize differences among modes of
variation by segregating smaller genera, we choose sis anthoecial profile elliptical, obovate in fruit; pre-
anthesis anthoecial compression subterete, some-
to recognize the continuum among these modes by
what dorsoventrally compressed in fruit; rachilla
using subgenera within Stipa sensu amplo, as did
terminating at floret attachment; disarticulation dis-
Freitag (1975), Clayton and Renvoize (1986), and
tal to the glumes. Glumes two, persistent, size and
rtheicWsenentelyawntVsipacezicqpiauetesezitnahasntedgorDteehgvearetsesagwei(ln1le9r9al6.i)k.eTlhyusr,ecwoembhianvee bshoadpyeapseuxb,eqruoauln,debdoatbhaxieaxltleyn,dmiengmbrbaenyoonuds tloecmhamra-
taceous, evident veins 1-9, green and purple prox-
selected a specific epithet that presents no nomen-
imally, colorless distally, glabrate or with midvein
cplhaetnuertailcbkaeryr,ieernatboledirdeicstcrtirmainnsafteirso.n oTfabtlhee n1,ewansdpe-a scabridulous dismtamlly; proximal (first or lower)
glume 3.2-5.1 long, profile asymmetrically
cies from similar regional stipoids.
lanceolate or oblongly lanceolate, apex acute to
Stipa shoshoneana Curto & D.M. Henderson, sp. acuminate, awnless; distal (second or upper) glume
nov. (Fig. 1). —TYPE: USA, Idaho, Salmon 3.3-5.3 mm long, profile asymmetrically ovate,
River Mts, ca. 15 km N of Challis, Morgan apex acute to acuminate, awnless. Lemma Callus
Creek Canyon ca. 7 km NW of US Hwy 93, obconic relative to pedicel, <0.3 mm long abaxi-
near 44°39'47"N, 114°13'19"W, Gooseberry ally, blunt, glabrate, articulation scarround, slightly
Creek 7.5 min quadrangle, T15N R19E S4 excavated, peripheral ring raised. LemmaBody 2.2-
SWV4 of NEVa, el. ca. 1675 m, aspect SW, 3.8 mm long; profile broadly elliptical; margins
along N side ofroad in cracks ofnear vertical symmetrically involute, juxtaposed parallely with
cliffs with Cercocarpus ledifolius Nutt., Heu- spikelet axis prior to anthesis, gaping in fruit; apex
chera grossulariifolia Rydb., Elymus spicatus emarginate about excurrent midvein; rounded abax-
(Pursh) Gould, and Poa interior Rydb., 30 ially; germination flap absent; texture coriaceous at
June 1987, L. Eno 17 (holotype: CAS; iso- anthesis; veins 5-7; evenly antrorsely hirtellous
types: BRY, ID, K, MIN, MO, NY, RM, UC, throughout, trichomes simple, <0.5 mm long, col-
US, UTC, WTU; all to be distributed). orless initially, aging tawny. Lemma Awn terminal,
unbranched, straight or slightly arcuate, antrorsely
mm
Stipa canadensis Poir. affinis, cujus habitum, an- scabridulous, 1.0-2.5 long; caducous. Palea

1998] CURTO AND HENDERSON: A NEW STIPA 61
2.1-3,6 mm long; length, texture and vestiture sub- Paratypes. USA, Idaho: Butte Co., Lemhi Range,
equal to lemma; profile broadly elliptical; margins ca. 35 km (air) NNW of Howe, Bunting Canyon
planar; apex bifid, minutely biaristate; rounded above Badger Mine, 44°06'21"N, 113°07'48"W,
abaxially; veins 2(3); disarticulating withrespective T9N R28E S16 SWV4, 2255 m, 12 July 1979, S. &
lemma; abaxial epidermal pattern similar to lemma P. Brunsfeld 1132 (ID); loc. cit., 16 June 1981, J.
pattern. Lodicules three, free, adaxial pair obovate, Civille 251d (ID); loc. cit, 13 June 1987, L. Eno 6
0.75-1.25 mm long, abaxial linear, 0.5-1.0 mm (ID); loc. cit., 26 June 1987, L. Eno 11 (ID); Lemhi
long. Stamens three; filaments free, evanescent to Range, ca. 12 km (air) NNE ofHowe, Middle Can-
marcescent; anthers free, penicillate, 1.75-2.2 mm yon, 43°53'30"N, 112°57'29"W, T7N R29E S26/35,
long, yellow. Ovularium obovate, glabrate; styles 1950-2255 m, 17 June 1978, D. M. Henderson
two, subterminal, free, short; stigmata two, exserted 4629, S. & P. Brunsfeld (ID, UTC); loc. cit., 16
laterally, white. Caryopsis obovoid, compression June 1981, J. Civille 260 (ID); loc. cit., 10 June
dorsoventral, length ca. 2 mm long; enclosed with- 1987, L. Eno 4, (ID); loc. cit., 25 June 1987, L. Eno
in, but free from anthoecium; exocarp smooth and 9 (ID); Custer Co., Salmon River Range, Loon
glossy; hilum linear, ca. 7/8 caryopsis length; endo- Creek ca. 500 m N of Bennett Creek Bridge,
sperm solid; embryo F+FF, % to Vi caryopsis 44°47'34"N, 114°48'02"W, T17N R14E S22 SE%,
length. Seedling mesocotyl lengthy; firstleaflamina 1400 m, 18 May 1988, L. Eno 25 (ID); ca. 4 km
narrow, erect, 7- to 15-veined. Chromosomes rela- (air) SE ofCougar Creek Ranch along Hood Creek,
tively small, 2-4 |x long, /i=10, 2/i=20 (fruits from 44°43'38"N, 114°52'38"W, T16N R13E S16 NE1/^
Eno 17, CAS), 2n=20 (fruits from Eno 18, CAS). 2000 m, 20 June 1982, J. Civille 309 (ID); Loon
LaminaAbaxial Epidermis without microhairs or Creek ca. 1.5 km NE of Tin Cup Campground,
papillae; costal/intercostal zonation conspicuous; 44°36'41"N, 114°47'50"W, T15N R14E S26 NW%,
costal regions: short-cells solitary, paired or in 1700 m, 2 July 1987, L. Eno 18 (ID); ca. 14 km
short rows, silica bodies round, square, horizontally (air) N of Challis, Morgan Creek Road ca. 5 km
nodular-elongate, irregulary dumbbell- or saddle- NW of US Hwy 93, 44°38'39"N, 114°12'32"W,
shaped, hooks infrequent, central, medium, prickles T15N R19E S10 NEVa SWV4, 1600 m, 14 June
infrequent, single file, small to medium, barb point- 1987, L. Eno 7 (ID); Lemhi Co., Salmon River
ing toward blade apex; intercostal regions: long- Range, Middle Fork Salmon River Canyon ca. 4.5
cells elongated, mostly 75-150 u, long, walls mod- km N of Bernard Creek Guard Station, ca. 800 m
erately thickened, side-walls parallel, undulations S of Jack Creek confluence, 45°00'22"N,
moderate, U-shaped, end-walls angled or interlock- 114°43'14"W, T19N R14E Sll NWVa, 1150 m, 19
ing, distributed in alternating long-cell/short-cell July 1982, J. Civille 335 (ID); ca. 55 km (air) NW
files with occasional short-cell pairs, intercostal of Challis, Middle Fork Salmon River Canyon at
short-cells square, rectangular, or irregular, silica Camas Creek confluence, 44°53'31"N,
body shape similar to cell shape, stomata low- 114°43'25"W, T18N R15E S16 SW%, 1160 m, 15
dome-shaped, arranged in single or double rows July 1982, J. Civille 332 (ID); ca. 55 km (air) NW
along costal zones, one or two interstomatal long- of Challis, Middle Fork Salmon River watershed,
cells between successive stomata, these occasion- Camas Creek ca. 400 m E ofMacarte Creek Camp,
ally separated by square to rectangular short-cells; 44°53'03"N, 114°41'36"W, T18N R15E S22, 1200
trirbasn,svmeirdsreibsegcetnieornalleyxhiibniditsitnigngpuirsohmaibnleentfroamdaxoitahl- Mm,ay1019J8u8n,eL.19E82n,oJ2.6Ci(vIiDl)l;ec2a.8955(IkD)m; (laoicr.) cNit.W, 1o9f
ers; sclerenchyma abundant interior to both epi- Challis, Middle Fork Salmon River watershed,
derms, forming ab- and adaxial vascular bundle Camas Creek between Dry Gulch and Forage
girders. Creek, 44°53'30"N, 114°34'57"W, T18N R16E S15
Lemma Abaxial Epidermis achnatheroid, costal/ SWV4, 1700 m, 7 July 1981, D. M. Henderson 5990
WNW
intercostal zonation absent; microhairs absent; pa- (ID); ca. 13 km of US Hwy 93, jet Salmon
pillae absent; stomata absent; long-cells ca. 10-30 NF Roads 045 (Iron Creek Rd) & 088 [sic, 046?],
(x long, walls moderately thickened, side-walls ir- 44°55'20"N, 114°06'43"W, T18N R20E S4 NWVa,
regularly undulating, end-walls irregular, arranged on quartzite cliffs, 3 July 1987, P. M. Peterson
in files as long-cell/short-cell/long-cell, long-cell/ 4764 & C. R. Annable (ID, UTC); Salmon River
short-cell/suberin-cell, or long-cell/prickle/long- Canyon, ca. 55 km N of Challis, US Hwy 93 ca.
cell; silica bodies horizontally oblong or squarish, 500 m N of mile 279, 400 m SE of highway op-
ca. 5-10 |x long; silico-suberose couples occasional, posite Iron Creek, 44°53'00"N, 113°57'56"W, T18N
suberin-cells crescentic, ca. 5 |x long; prickles 20- R21E S15 SEV4 SW%, 1400 m, 14 June 1978, D.
25 fx long, barb short. M. Henderson 4432 (ID); loc. cit., 12 July 1981, J.
Fig. 1. Stipa shoshoneana. a) habit; b) spikelet; c) floret; d) lemma abaxial epidermis; e) lemma callus; f) caryopsis,
abaxial view; g) distribution of largest Idaho populations.
MADRONO
62 [Vol. 45
Civille 276 (ID); loc. cit., 21 June 1987, L. Eno 8 Epithet etymology. The specific epithet refers to
(ID); loc. cit., 28 June 1987, L. Eno 13 (ID); Salm- the Northern and Western Shoshone people whose
on River Range, Middle Fork Salmon River water- ancestral lands encompass the entire known distri-
shed, Loon Creek ca. 3 km NW of Falconberry bution of this species.
Guard Station, between Mearney Creek and Burn
Creek, 44°42'07"N, 114°46'41"W, T16N R14E S24 Phenetic Key
(sSIiWDdV)e;4caVN.aWlVl14e.5y, kC1om5.0,0NMmio,dfd6lGeoJulFldoyernk19C8Sr2ae,lemkJ.,onCTioRvmiilvblesert,3o3nWe0 1 euStqpyuolanelsctaforuysaoenpdtshiposr;eocxpiirmuoamxllilyme,anglptehgr.lsiusmteinlgenasgtahcsehnotrrtiecr"tbheanako"r
Rock, 45°09'44"N, 114°43'26"W, T21N R14E S15 2 Lemma awn 1-2.5 mm long, exserted subapically,
NSeEVvaadNa:EVN4y, e10C2o5.,m,Bel2t0edMaRyang1e9,88N, Lo.fECnlioff2S7pr(iInDg),; isturmaisghptecoirmewnesa;klaynthaerrcsuagtlea,broaftteenorarbasreenltyopennihceirlblaart-e
37°30'45"N, 116°05'15"W, T5S R53E S8, 2170 m, distally; stigmata 2 Oryzopsispungens
infrequent at cliff base, 18 June 1995, F. J. Smith 2' Lemma awn 3-8 mm long, exserted abaxially, re-
3936 & J. Heers (UNLV). curved or geniculate at midlength, some usually
presenton herbarium specimens; antherspenicillate
Distribution. Stipa shoshoneana is known prin- distally; stigmata 3 Oryzopsis exigua
cipally from canyons of the Middle Fork of the 1' Styles free throughout, persisting as lateral "horns"
aSsalamnodnLRoiovnerCarnedekfsr,omexittesnedaisntgercna.tri1b6ut0arkiems,bCyamai-r um3aploAnngtlchauromyeeocpliseiunsmg,thaovrleowrniagtgehirngntoha<vn3isainmbtlmehopeelcroisnuigs,mtelgnelcnaegb;trhap.treoxio-r
southeast to the southern Lemhi Range (Fig. 1). Sti- sparsely antrorsely puberulent, trichomes adpressed
pa shoshoneana is also curiously disjunctnearCliff Oryzopsis micrantha
Spring in the Belted Range ofsouth-central Nevada 3' Anthoecium averaging > 3 mm long, evidently
about 750kmby air southwest ofthe most southern evenly antrorselyhirtelloustohirsute,trichomesde-
bIldeahporepsoepnucleatiinotnh.eTihnitesrcdailsajruyncrtainognessuogfgeeassttserpnosNsei-- 4flexLeidg.ule <1.0 mm long, longer laterally than me-
vada. Searches by Curto at some potential sites in d5ialPlya.lea ^ % lemma body length; lemma awn
tShneakJea,rbWihdiget,e IPinndee,peannddenQcue,innRuCbya,nyoScnheRlalngCerseeko,f w<e7aklmymonlcoen-gg,eniccounltaotret,edca<duco1usr;evpolruitmiaorny,
eastern Nevada found populations of O. exigua or panicle branches short, erectly adpressed to
O. micrantha, but no S. shoshoneana populations. rachis at maturity .... Oryzopsis swallenii
5' Palea <Vi lemma body length; lemma awn
Habitat. Stipa shoshoneana is nearly always 18-30 mm long, contorted > 1 revolution
found within moist crevices of intrusive or extru- proximally, twice-geniculate, persistent; pri-
sive igneous, metamorphic, or sedimentary cliffs mary panicle branches elongate, deflexed
and rock walls. Typical associate species include: from rachis at maturity
HDoeuugclh.e,raPotegnrtoislslualargiliafnodliualosRaydLbi.n,dl.R,ibEelsymucsersepuim- 4' Ligule > 1.5 mm long, acuteSttoipaatterniucahtaer.dsonii
catus (Pursh) Gould, Poa interior Rydb., and Poa 6 tLheermeamfatera,wn8-p2e0rsimstmentluonntgi,l fsrtuoiutt,matounrciet-y oorr
secunda K. B. Presl, with other taxa, such as Pseu- twice-geniculate,proximalsegmentdistinctly
dotsuga menziesii (Mirb.) Franco, Cercocarpus led- spirally contorted; anthers glabrate
ifolius Nutt., Artemisia tridentata Nutt., Amelan- Stipa canadensis
chier alnifolia Nutt., Glossopetalon spinescens A. 6' Lemma awn caducous, 1-2.5 mm long,
Gray, Mimulus cusickii (Greene) Piper, Petrophyton straightorweakly arcuate; antherspenicillate
caespitosum (Nutt.) Rydb., and the east-central Ida- Stipa shoshoneana
ho endemics, Astragalus amnis-amissi Barneby,
&
Cryptantha salmonensis (Nels. Macbr.) Pays., or
Draba oreibata Macbr. & Pays., being locally com- Acknowledgments
mon at some sites. Special thanks to LeAnn Eno and Janey Civille for the
arduous fieldwork effected in collecting the bulk of the
Chromosome number significance. Stipa shosh- Stipa shoshoneana specimens. All fieldwork by Civille,
oneana plants possess the fewest chromosomes Curto, Eno, and Henderson was funded through the C. R.
(2/1=20) of all North American Stipeae counted to Stillinger Trust, University of Idaho. Anita Cholewa pro-
date, and the second-lowest somatic number ever videdsome additional fieldcollectionsandherbariumsup-
reported for the tribe; Prokudin et al. (1977) re- port. Mary Barkworth allowed access to herlab and to all
ported 2/1=18 for S. bromoides (L.) Doerfler (as of the histological preparations made for her previous
Achnatherum bromoides [L.] Nevski). Chapanov analyses. Dave Keil corrected ourLatin diagnosis and as-
sisted with our chromosome counts. Dieter Wilken pro-
and Yurtsev (1976) reported 2/i=20 for the Asian vided a much appreciated thorough review that improved
species Piptatherum vicarium (Grig.) Roshev., al- this paper. Rhonda Riggins offered helpful comments
though all otherreports indicate 2«=24 forthis spe- about an earlier draft. Marianne Filbert prepared the fine
cies, the common number ofPiptatherum sect. Pip- illustrations of S. shoshoneana macromorphology. Dave
tatherum. Fross and staffofNative Sons Nursery propagated plants
1998] CURTO AND HENDERSON: A NEW STIPA 63
W
from seed. Lastly, thanks to the herbaria cited for their Jacobs, S. L. andJ. Everett. 1996.Austrostipa, anew
provision of loaned specimens. genus, and new names for Australasian species for-
merly included in Stipa (Gramineae). Telopea 6:579-
595.
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