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serpentine reed grass

one-and-a-half-flower reedgrass

Habit Plants usually with sterile culms; usually cespitose, often with rhizomes 2-15 cm long, 1-3 mm thick. Plants rarely with sterile culms; strongly cespitose, usually without rhizomes, sometimes with rhizomes 1-2 cm long, 1-2 mm thick.
Culms

(30) 55-80(100) cm, unbranched, scabrous beneath the panicles;

nodes (1)2(5).

(15)30-46(50) cm, unbranched, usually smooth, rarely slightly scabrous beneath the panicles;

nodes 1-2(3).

Sheaths

and collars usually scabrous, rarely smooth;

ligules (0.5)2-5.5(7) mm, usually truncate, entire to slightly lacerate;

blades (8)10-20(27) cm long, (1.5)2-3(4) mm wide, usually involute, abaxial surfaces usually scabrous, rarely smooth, adaxial surfaces scabrous, glabrous or sparsely hairy, both surfaces with abundant white glands between the veins, visible only with magnification.

and collars smooth;

ligules (0.5)2-5(6) mm, usually truncate, sometimes obtuse, usually entire, sometimes lacerate;

blades (3)8-25(31) cm long, (2)3-7 mm wide, flat, abaxial surfaces usually scabrous, rarely smooth, adaxial surfaces smooth or slightly scabrous, glabrous or sparsely hairy.

Panicles

(6)8-11(15) cm long, (1)1.2-1.5 cm wide, contracted, mostly erect, pale green to green;

branches 2-4(4.5) cm, scabridulous, usually spikelet-bearing to the base.

4-11(12) cm long, 0.8-2.5(2.8) cm wide, erect, contracted to somewhat open, usually purple-tinged, sometimes brown or green;

branches 1.5-3(4) cm, scabrous, prickles sometimes almost hairlike, usually spikelet-bearing to the base, lowest branches sometimes not so.

Spikelets

(4.5)5-7(8) mm;

rachilla prolongations about 1.5 mm, hairs 1-2 mm.

(5)5.5-8.5(9.5) mm;

rachilla prolongations (1)1.5(2.2) mm, hairs 1-2.2 mm.

Glumes

keeled, usually scabrous over the entire surface, rarely only the keels scabrous distally, lateral veins prominent, apices acute to acuminate;

callus hairs 1-1.5(2) mm, 0.2-0.4 times as long as the lemmas, sparse;

lemmas 4.5-6.5 mm, 0-2 mm shorter than the glumes;

awns 5-6(8) mm, attached to the lower 1/10 – 1/5 of the lemmas, exserted less than 2 mm, stout, distinguishable from the callus hairs, bent;

anthers (2.5)3-3.5(4) mm.

keeled, keels usually scabrous for their whole length, sometimes the surfaces also scabrous, lateral veins prominent, apices long-acuminate, usually twisted distally;

callus hairs (0.8)1.2-1.8(3) mm, 0.1-0.4 times as long as the lemmas, abundant;

lemmas (3.5)4-4.5(6) mm, (0.5)1-2.5(4.5) mm shorter than the glumes;

awns (5.4)7-11(13) mm, attached to the lower 1/10 – 2/5 of the lemmas, exserted more than 2 mm, stout, easily distinguished from the callus hairs, bent;

anthers (1.2)2.2-3(3.4) mm.

2n

= 28.

= 28.

Calamagrostis ophitidis

Calamagrostis sesquiflora

Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Calamagrostis ophitidis grows in meadows, seeps, grasslands, and chaparral, as well as in coniferous forests, on serpentine outcrops and soils, at 50-1100 m. It is known only from Sonoma, Marin, Mendocino, Lake, and Napa counties in California.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Calamagrostis sesquiflora grows at 0-1000 m in open heath, meadows, and forest openings, on or at the base of open rocky cliffs and knolls, as well as in moist talus. It grows in strictly maritime habitats along the west coast of North America, from the Aleutian Islands in Alaska to the Queen Charlotte Islands and south to Vancouver Island (Brooks Peninsula) in British Columbia. There is also a single collection from the coast of mainland British Columbia. In northeast Asia, it ranges into the Kamchatka Peninsula and Kuril Archipelago.

Some specimens from the northwestern United States are incorrectly identified, partly because an earlier name for Trisetum spicatum (L.) K. Richt. was Trisetum sesquiflorum Trin.

Calamagrostis sesquiflora has sometimes included C. tacomensis (see next) [as C. vaseyi Beal]. Several specimens that were previously identified as C. sesquiflora are actually C. tacomensis. Calamagrostis sesquiflora differs in preferring moister habitats, having wider leaves, callus hairs that are shorter relative to the lemmas, shorter panicle branches, and glumes that are often twisted at the apices.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 712. FNA vol. 24, p. 714.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Calamagrostis Poaceae > subfam. Pooideae > tribe Poeae > Calamagrostis
Sibling taxa
C. bolanderi, C. breweri, C. cainii, C. canadensis, C. cinnoides, C. deschampsioides, C. epigejos, C. foliosa, C. howellii, C. koelerioides, C. lapponica, C. montanensis, C. muiriana, C. nutkaensis, C. perplexa, C. pickeringii, C. porteri, C. purpurascens, C. rubescens, C. scopulorum, C. sesquiflora, C. stricta, C. tacomensis, C. tweedyi, C. ×acutiflora
C. bolanderi, C. breweri, C. cainii, C. canadensis, C. cinnoides, C. deschampsioides, C. epigejos, C. foliosa, C. howellii, C. koelerioides, C. lapponica, C. montanensis, C. muiriana, C. nutkaensis, C. ophitidis, C. perplexa, C. pickeringii, C. porteri, C. purpurascens, C. rubescens, C. scopulorum, C. stricta, C. tacomensis, C. tweedyi, C. ×acutiflora
Synonyms C. purpurascens var. ophitidis C. purpurascens subsp. tasuensis, C. purpurascens subsp. arctica, C. arctica
Name authority (J.T. Howell) Nygren (Trin.) Tzvelev
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