Poa confinis

Vasey
Common names: Coastal bluegrass
Endemic
Treatment appears in FNA Volume 24. Treatment on page 552.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants perennial; densely to loosely tufted, rhizomatous and stoloniferous, rhizomes and stolons to 1 m, slender. Basal branching mainly intravaginal, some extravaginal. Culms 7-30 (35) cm tall, 0.4-0.9 mm thick, slender, erect or the bases decumbent, terete or weakly compressed; nodes terete, 0-1 exserted. Sheaths closed for 1/3-2/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1) 1.4-4.5 times blade lengths; collars smooth, glabrous; ligules 0.5-1.5 (2.2) mm, scabrous, truncate to acute; innovation blades adaxially moderately to densely scabrous or hispidulous on and between the veins; cauline blades slightly reduced in length distally, 0.5-1 (1.5) mm wide, involute, thin to moderately thick, usually filiform, soft, abaxial surfaces smooth, adaxial surfaces sparsely scabrous on and between the veins, apices narrowly prow-shaped, flag leaf-blades (0.5) 1-5 cm. Panicles 1-5 (7) cm, erect, ovoid, fairly tightly to loosely contracted, congested or moderately congested, with fewer than 50 spikelets; nodes with 1-2 branches; branches 0.5-3 cm, erect to ascending, slightly lax, terete or angled, angles sparsely to densely scabrous, with 2-12 spikelets. Spikelets 3-6 (8) mm, lengths to 3 times widths, laterally compressed, compact, not sexually dimorphic; florets 2-5; rachilla internodes 0.8-1.1 mm, usually not readily visible from the sides, glabrous or sparsely puberulent. Glumes slightly unequal, distinctly keeled, keels smooth or scabrous; lower glumes 2-4 mm, 1-3-veined, about 2/3 the length of the adjacent lemmas; upper glumes 2.9-5 mm; calluses usually diffusely webbed, hairs 1-2 mm, infrequently glabrous; lemmas 2.5-4 (4.5) mm, lanceolate, distinctly keeled, moderately to densely finely scabrous, glabrous throughout or the keels and sometimes the marginal veins sparsely puberulent proximally, margins narrowly scarious, glabrous, apices acute; paleas subequal to the lemmas, keels scabrous, intercostal regions glabrous; anthers vestigial (0.1-0.2 mm) or 1.5-2 mm. 2n = 42.

Distribution

Calif., Oreg., Wash., B.C.

Discussion

Poa confinis grows on sandy beaches and forest margins of the west coast, a habitat that is being lost to invasion by exotic species and development. It is closely related to P. diaboli (see next), from which it differs by a suite of characters. The two species are ecologically and geographically distinct. Poa confinis differs from P. pratensis (p. 522) in having glabrous or sparsely hairy lemmas and diffusely webbed calluses. It is gynodioecious.

Selected References

None.

Lower Taxa

None.

"thin" is not a number."reduced" is not a number."thin" is not a number."decumbent" is not a number.

... more about "Poa confinis"
membranous +  and scarious +
hairy +, hispidulous +  and scabrous +
5 cm50 mm <br />0.05 m <br /> (?) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
scarious-hyaline +
acute +  and prow--shaped +
Robert J. Soreng +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
keeled +  and rounded +
strigose +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
compressed +  and terete +
swelling +
not evident +
involute +, folded +  and flat +
erect;ascending +
hispidulous +, glabrous +, scabrous +  and smooth +
angled +  and terete +
0.5 cm5 mm <br />0.005 m <br /> (3 cm30 mm <br />0.03 m <br />) +
compressed +  and terete +
soft +  and firm +
Coastal bluegrass +
unbranched +  and hollow +
7 cm70 mm <br />0.07 m <br /> (30 cm300 mm <br />0.3 m <br />) +
compressed +  and terete +
slender +
7 cm70 mm <br />0.07 m <br /> (70 cm700 mm <br />0.7 m <br />) +
not woody +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
Calif. +, Oreg. +, Wash. +  and B.C. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
2 +  and 5 +
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 /> (0.2 cm2 mm <br />0.002 m <br />) +
0 +  and 1/6 +
Oval (?) +  and Round (?) +
hispidulous +  and scabrous +
milky white +  and slightly greenish +
puberulent +
moderately prominent +  and prominent +
5-7(11)-veined +
keeled +  and lanceolate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
membranous +
erose +  and entire +
colorless +  and milky white +
truncate +  and acute +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
membranous +
inconspicuous +
lobed +  and lanceolate +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
milky white +  and slightly greenish +
concealed +  and prominent +
0 +  and 1 +
2 +  and 1 +
well-developed +
2-keeled +
subequal +
7 cm70 mm <br />0.07 m <br /> (?) +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
dry +  and fleshy +
puberulent +  and glabrous +
rhizomatous +  and stoloniferous +
not bulbiferous +
2 +  and 12 +
compressed +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
1 +  and 3 +
simple +  and compound +
extravaginal +, intravaginal +  and basal +
slender +
0 cm0 mm <br />0 m <br /> (100 cm1,000 mm <br />1 m <br />) +
2 (?) +  and 3 (?) +
Gramineae +
Poa confinis +
Poa subsect. Madropoa +
species +
membranous +
5-veined +  and 3-veined +
0.29 cm2.9 mm <br />0.0029 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
parallel +  and converging +
aquatic +  and terrestrial +