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bulbous blue grass

bluegrass

Habit Plants perennial; densely tufted, not rhizomatous, not stoloniferous. Plants perennial; densely tufted, not stoloniferous, not rhizomatous.
Culms

15-60 cm, erect or spreading, bases bulbous.

10-35 cm, erect or the bases decumbent;

nodes terete, 0-1 exserted.

Sheaths

closed for about 1/4 their length, terete, lowest sheaths with swollen bases;

ligules 1-3 mm, smooth or scabrous, apices obtuse to acute;

blades 1-2.5 mm wide, flat, thin, lax, soon withering.

closed for 1/4-3/4 their length, terete, apices acuminate;

innovation blades 0.5-1(2) mm wide, involute, moderately thick, moderately firm, abaxial surfaces smooth or scabrous, adaxial surfaces usually densely scabrous or hispidulous;

cauline blades usually gradually reduced distally, 0.5-1(2) mm wide, flat, folded, or involute, thin, sometimes withering, abaxial surfaces smooth or scabrous, apices narrowly prow-shaped, sometimes the flag leaf blades vestigial.

Basal branching

intravaginal.

intra-vaginal.

Panicles

3-12 cm, ovoid;

nodes with 2-5 branches;

branches ascending to spreading, terete, usually smooth or sparsely scabrous, infrequently moderately scabrous.

2-8 cm, erect, narrowly lanceoloid to ovoid, contracted, congested;

nodes with 1-2 branches;

branches 0.5-3 cm, erect, terete to angled, scabrous.

Spikelets

3-5 mm, laterally compressed, usually bulbiferous;

florets 3-7, the basal floret, and sometimes additional florets, normal;

rachilla internodes smooth, glabrous.

4-8 mm, lengths to 3 times widths, broadly lanceolate to narrowly ovate, laterally compressed, not sexually dimorphic;

florets 2-5;

rachilla internodes 0.5-1.2 mm, smooth or scabrous.

Glumes

keeled, keels scabrous;

lower glumes 3-veined;

upper glumes shorter than or subequal to the lowest lemmas;

calluses webbed or glabrous;

lemmas 3-4 mm, lanceolate, keeled, glabrous or the keels and marginal veins short- to long-villous, intercostal regions glabrous or softly puberulent, apices acute;

paleas scabrous, keels often softly puberulent at midlength;

anthers 1.2-1.5 mm and functional, sometimes aborted late in development, sometimes not developed.

lanceolate, distinctly keeled;

lower glumes 3-veined, distinctly shorter than the lowest lemmas;

calluses glabrous;

lemmas 4-7 mm, lanceolate, distinctly keeled, membranous, keels and marginal veins usually softly puberulent, sometimes short-villous, intercostal regions usually glabrous, infrequently softly puberulent proximally, lateral veins moderately prominent, margins glabrous, apices acute;

palea keels scabrous;

anthers mostly vestigial (0.1-0.2 mm), rarely 2-3 mm.

2n

= 14, 21, 28, 39, 42, 45.

= unknown.

Poa bulbosa

Poa ×nematophylla

Distribution
from FNA
AR; AZ; CA; CO; CT; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MT; NC; ND; NE; NJ; NM; NV; NY; OH; OK; OR; PA; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; ID; MT; ND; UT; WY; AB; BC; MB; SK
[BONAP county map]
Discussion

Poa bulbosa is a European species that is now established in the Flora region. In southern Europe and the Middle East, it is considered an important early spring forage.

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

Poa ×nematophylla is believed to consists of hybrids between P. cusickii subsp. pallida (see previous) and P. fendleriana (p. 556). It is mostly pistillate and apomictic; few staminate plants have been found. It usually resembles P. cusickii most, but grades towards P. fendleriana. It tends to grow on drier slopes than either parent, mainly in and around sagebrush desert/forest interfaces.

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

Key
1. Spikelets not bulbiferous
subsp. bulbosa
1. All or some spikelets bulbiferous
subsp. vivipara
Source FNA vol. 24, p. 516. FNA vol. 24, p. 562.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Arenariae Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Epiles
Sibling taxa
P. abbreviata, P. alpina, P. alsodes, P. ammophila, P. annua, P. arachnifera, P. arctica, P. arida, P. arnowiae, P. atropurpurea, P. autumnalis, P. bigelovii, P. bolanderi, P. chaixii, P. chambersii, P. chapmaniana, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. cuspidata, P. diaboli, P. douglasii, P. eminens, P. fendleriana, P. glauca, P. hartzii, P. howellii, P. infirma, P. interior, P. keckii, P. kelloggii, P. laxa, P. laxa × glauca, P. laxiflora, P. leibergii, P. leptocoma, P. lettermanii, P. macrantha, P. macrocalyx, P. marcida, P. napensis, P. nemoralis, P. nervosa, P. occidentalis, P. paludigena, P. palustris, P. paucispicula, P. piperi, P. porsildii, P. pratensis, P. pringlei, P. pseudoabbreviata, P. reflexa, P. rhizomata, P. saltuensis, P. secunda, P. sierrae, P. stebbinsii, P. stenantha, P. strictiramea, P. sublanata, P. suksdorfii, P. supina, P. sylvestris, P. tenerrima, P. tracyi, P. trivialis, P. unilateralis, P. wheeleri, P. wolfii, P. ×gaspensis, P. ×limosa, P. ×nematophylla
P. abbreviata, P. alpina, P. alsodes, P. ammophila, P. annua, P. arachnifera, P. arctica, P. arida, P. arnowiae, P. atropurpurea, P. autumnalis, P. bigelovii, P. bolanderi, P. bulbosa, P. chaixii, P. chambersii, P. chapmaniana, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. cuspidata, P. diaboli, P. douglasii, P. eminens, P. fendleriana, P. glauca, P. hartzii, P. howellii, P. infirma, P. interior, P. keckii, P. kelloggii, P. laxa, P. laxa × glauca, P. laxiflora, P. leibergii, P. leptocoma, P. lettermanii, P. macrantha, P. macrocalyx, P. marcida, P. napensis, P. nemoralis, P. nervosa, P. occidentalis, P. paludigena, P. palustris, P. paucispicula, P. piperi, P. porsildii, P. pratensis, P. pringlei, P. pseudoabbreviata, P. reflexa, P. rhizomata, P. saltuensis, P. secunda, P. sierrae, P. stebbinsii, P. stenantha, P. strictiramea, P. sublanata, P. suksdorfii, P. supina, P. sylvestris, P. tenerrima, P. tracyi, P. trivialis, P. unilateralis, P. wheeleri, P. wolfii, P. ×gaspensis, P. ×limosa
Subordinate taxa
P. bulbosa subsp. bulbosa, P. bulbosa subsp. vivipara
Synonyms P. cusickii subsp. pubens
Name authority L. Rydb.
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