Poa porsildii

Gjaerev.
Common names: Porsild's bluegrass
Endemic
Treatment appears in FNA Volume 24. Treatment on page 563.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants perennial; densely tufted, not stoloniferous, not rhizomatous. Basal branching intravaginal. Culms (12) 17-30 (40) cm, erect or the bases decum¬bent, with (0) 1 (2) exserted nodes. Sheaths closed for 1/3 – 2/3 their length, terete, bases of basal sheaths glabrous; collars smooth, glabrous; ligules of cauline leaves 1-2 mm, smooth, apices truncate to obtuse, ligules of the innovation leaves shorter than 0.5 mm, scabrous, truncate; innovation blades not or indistinctly differentiated from the cauline blades, flat or weakly involute, adaxial surfaces sparsely to fairly densely finely scabrous between the veins; cauline blades 1-3 mm wide, folded, fairly thin to moderately thick, soft, abaxial surfaces smooth, apices narrowly prow-shaped. Panicles 2-5 (6) cm, erect or nodding, ovoid to pyramidal, slightly contracted or open, sparse, with fewer than 20 spikelets; nodes with 1-2 branches; branches 2-4 cm, ascending to widely spreading, occasionally reflexed, flexuous, lax, slender, terete, smooth or sparsely scabrous, with 1-3 (4) spikelets. Spikelets 4-7 mm, lengths to 3 times widths, broadly lanceolate to narrowly ovate, laterally compressed, not sexually dimorphic, often strongly anthocyanic; florets 3-4; rachilla internodes smooth, glabrous or sparsely puberulent. Glumes thin, somewhat lustrous, distinctly keeled, keels smooth; lower glumes 3-veined, distinctly shorter than the lowest lemmas; calluses glabrous; lemmas 4-6 mm, lanceolate, distinctly keeled, thinly membranous, sparsely to moderately densely and finely scabrous, usually glabrous, rarely sparsely softly puberulent proximally, lateral-veins moderately prominent, margins glabrous, apices acute; palea keels sparsely to moderately densely scabrous; anthers vestigial (0.1-0.2 mm) or 2.5-3 mm. 2n = unknown.

Discussion

Poa porsildii is an alpine, calciphilic, mesophilic, dioecious species that grows from eastern Alaska to the western Northwest Territories. It differs from P. cusickii subsp. purpurascens (p. 562) in having panicles with laxer, smooth, and more slender branches, lemmas that are usually glabrous, and in having staminate plants.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Poa porsildii"
membranous +  and scarious +
smooth or +  and moderately densely scabrous glabrous or hispidulous +
5 cm50 mm <br />0.05 m <br /> (?) +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
scarious-hyaline +
Acute (?) +, Prow--shaped (?) +, Truncate (?) +  and Obtuse (?) +
Robert J. Soreng +
Gjaerev. +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
keeled +  and rounded +
strigose +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
involute +, folded +  and flat +
thin;thick +
5 cm50 mm <br />0.05 m <br /> (?) +
reflexed;ascending;widely spreading +
hispidulous +, glabrous +, scabrous +  and smooth +
slender +
compressed +  and terete +
prow--shaped +, involute +, folded +  and flat +
soft +  and firm +
fairly thin;moderately thick +
Porsild's bluegrass +
unbranched +  and hollow +
compressed +  and terete +
17 cm170 mm <br />0.17 m <br /> (30 cm300 mm <br />0.3 m <br />) +
not woody +
Alaska +, N.W.T. +  and Yukon +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
3 +  and 4 +
compressed +
reduced +
2mm +  and 10mm +
1-3(5)-veined +
shorter or longer +
subtending +
unequal +
distributed +
uncinate +
0.1 cm1 mm <br />0.001 m <br /> (?) +
0 +  and 1/6 +
Oval (?) +  and Round (?) +
milky white +  and slightly greenish +
hairy +  and glabrous +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
5(7-11)-veined +
puberulent +  and glabrous +
keeled +  and lanceolate +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
membranous +
erose +  and entire +
colorless +  and milky white +
ciliolate +  and glabrous +
truncate +  and acuminate +
0.5 cm5 mm <br />0.005 m <br /> (?) +
membranous +
inconspicuous +
lobed +  and lanceolate +
milky white +  and slightly greenish +
concealed +  and prominent +
0 +  and 5 +
compressed +  and terete +
2 +  and 1 +
well-developed +
2-keeled +
subequal +
6 cm60 mm <br />0.06 m <br /> (?) +
nodding +  and erect +
ovoid +  and pyramidal +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
dry +  and fleshy +
puberulent +, glabrous +  and smooth +
pubescent +, glabrous +, scabrous +  and smooth +
rhizomatous +  and stoloniferous +
not bulbiferous +
compressed +, broadly lanceolate +  and narrowly ovate +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Poa porsildii +
Poa subsect. Epiles +
species +
membranous +
5-veined +  and 3-veined +
parallel +  and converging +
branching +, not rhizomatous +  and not stoloniferous +
aquatic +  and terrestrial +