Agrostis idahoensis Nash, Bull. Torrey Bot. Club 24(1): 42-43. 1897.

Vigosa-Mercado, J. Luis, Delgado-Salinas, Alfonso, Alvarado Cardenas, Leonardo O. & Eguiarte, Luis E., 2023, Revision of the genus Agrostis (Poaceae, Pooideae, Poeae) in Megamexico, PhytoKeys 230, pp. 157-256 : 157

9. Agrostis idahoensis Nash, Bull. Torrey Bot. Club 24(1): 42-43. 1897.

Fig. 20

= Agrostis tenuis Vasey, Bull. Torrey Bot. Club 10(2): 21. 1883, nom. illeg. hom., non Sibth., 1794. Agrostis tenuiculmis Nash, Mem. New York Bot. Gard. 1: 32. 1900. Type: USA. California: San Bernardino County, on the San Bernardino Mountains, Aug 1881 or 1882, S.B. Parish and W.F. Parish 1085 (holotype: US (US00131119 [image!]).

= Agrostis filiculmis M.E. Jones, Contr. W. Bot. 14: 13. 1912. Type: USA. Arizona: Little De Motte Park on the Kaibab in N Arizona, 19 Sep 1894, M.E. Jones 6056bb (holotype: RSA (RSA0000394 [image!]).*

Type.

USA. Idaho: Nez Perce County, Forest , 1160 m alt., 1 Jul 1896, A.A. Heller and E.G. Heller 3431 (holotype: NY (NY00327633 [image!]); isotypes: BAA (BAA00001339 [image!]), CAS (CAS0000194 [image!]), DAO (DAO000465362 [image!]), ID (ID00157714 [image!]), JE (JE00020223[image!]), K (K000838198 [image!]), LE (LE00009307 [image!]), MO (MO-123094 [image!]), MIN (MIN1000077 [image!]), MSC (MSC0129856 [image!]), NDG ( NDG07456 [image!]), NY (NY00327634 [image!]), P (P00740552 [image!], P00740553 [image!]), S (SG-259 [image!]) , US ( US 00131762 [image!]).

Description.

Plants perennial, caespitose. Tillers extravaginal, with cataphylls. Culms 8-40 cm long, erect, nodes 2-5, glabrous, internodes glabrous. Leaves mostly basal; sheaths 5-11 cm long, the lower ones usually shorter larger than the internodes, glabrous or scaberulous; ligules (0.7-)1-2(-4) mm long, longer than wide, dorsally scaberulous, apices rounded to truncate, erose to lacerate; blades 1-7 cm long, 0.5-2 mm wide, linear, flat, often becoming involute when dry, scaberulous on both surfaces. Panicles 3-13 cm long, 1-6(-8) cm wide, open, lax, lanceolate to ovate, exserted from the upper sheaths; branches ascending, sometimes spreading, rebranching about or slightly above mid-length, scaberulous, without spikelets near their base, inferior branches 1-4 cm long; pedicels 0.5-6.5 mm long, ascending to spreading, scaberulous. Spikelets 1.5-2.5 mm long, purplish; glumes subequal, lanceolate, apices acute to shortly acuminate, 1-veined, scaberulous on the keel, lower glume 1.5-2.5 mm long, upper glume 1.4-2.4 mm long, sometimes glabrous; callus puberulous; lemmas 1.2-2.2 mm long, elliptic, apices entire, acute to obtuse, 5-nerved, veins inconspicuous, unawned; paleas absent or up to 0.2 mm long, veinless, glabrous; anthers 3, 0.3-0.6 mm long. Caryopsis 1-1.3 mm long, elliptic; endosperm soft. 2n= 28 ( Harvey 2007).

Anatomy and micromorphology.

Not seen.

Distribution and habitat.

Agrostis idahoensis is distributed from Alaska to California and New Mexico ( Harvey 2007). It is also present in Chile and Argentina ( Rúgolo and Molina 1997). In the study zone, this species has been collected in southern Arizona and California (Fig. 18C ). It grows in stream edges of temperate forests, with Abies , Arctostaphylos , Picea or Pinus , between 3084-3121 m a.s.l. (Fig. 9L ). There are more records of this species in the study zone, on databases ( GBIF 2023b), but not all of them have images, and thus we were unable to confirm their identity.

Phenology.

Specimens with spikelets have been collected in July and August (Fig. 10L ).

Commentaries.

Agrostis idahoensis is similar to A. perennans sensu lato. It differs from it in the mostly basal leaves, persistent, with leaf blades 0.5-2 mm wide (vs. basal and cauline leaves, the basal ones often drying before anthesis, with leaf blades often more than 2 mm wide in A. perennans ). It is also similar to A. scabra , from which it differs in the branches of the panicle rebranching about or slightly above mid-length, and spikelets not clustered at the branch tips (vs. branches rebranching in the upper third, spikelets somewhat clustered in A. scabra ). Agrostis idahoensis is scarcely different from A. turrialbae , distributed from central Mexico to Central America. The former differs in flatter and wider leaf blades, 0.5-2 mm wide (vs. conduplicate or involute leaf blades, 0.3-0.5 mm wide in A. turrialbae ).

Conservation status.

Herbarium specimens from only two localities in the United States were examined, whereby the EOO and AOO cannot be calculated. The category of Deficient Data (DD) is suggested.

Specimens examined.

USA. Arizona: Graham County, High Peak Cienega, Pinaleno Mountains , 32.693861°N, 109.867556°W, 3121 m alt., 9 Aug 2014, M. Licher 4524 (ASC) . California: San Bernardino County, San Bernardino National Forest, San Gorgonio Wilderness area, High Meadow Springs in the upper watershed of Mill Creek , approximately 0.75 air miles west northwest of Dollar Lake , 34.12471°N, 116.86665°W, 3084 m alt., 21 Jul 2016, D.S. Bell and A. Chambers 9968 (RSA) .

Figures

Figure 9. Elevation histograms of Agrostis species A all records B native species C introduced species D A. bourgaei E A. calderoniae F A. capillaris G A. elliottiana H A. exarata I A. ghiesbreghtii J A. gigantea K A. hyemalis L A. idahoensis M A. laxissima N A. microphylla O A. pallens.

Figure 10. Phenology histograms of Agrostis species A all records B native species C introduced species D A. bourgaei E A. calderoniae F A. capillaris G A. elliottiana H A. exarata I A. ghiesbreghtii J A. gigantea K A. hyemalis L A. idahoensis M A. laxissima N A. microphylla O A. pallens.

Figure 18. Map of known geographic distribution of Agrostis species, based on herbarium specimen data A A. gigantea B A. hyemalis C A. idahoensis D A. laxissima E A. microphylla F A. pallens.

Figure 20. Herbarium specimen of Agrostis idahoensis. Based on Bell and Chambers 9968 (RSA). Scale bar: 3 mm.