2024 Edition • Get the App
X

Colors

Data mode

Account

Login
Sign up

X
Keyed in multiple places:

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Poaceae, Key C: bur, bead, or bulblet grasses of various tribes

Copy permalink to share | Check for keys that lead to this key

1 Fertile spikelets absent (spikelets modified into asexual, purplish bulblets) or variously spiny or bead like; [tribe Poeae]
 Poa
1 Fertile spikelets variously spiny or bead-like.
  2 Pistillate spikelets concealed within a hard, beadlike shell, this white, black, or variously colored; [tribe Andropogoneae]
  2 Spikelets concealed in a variously spiny bur, this green or tan, sometimes with pink or purple shading.
    3 Bur formed from accrescent branchlets, with fewer and less regularly arranged straight prickles (these typically retrorsely scabrous); [tribe Paniceae]
    3 Bur formed from an enlarged glume, with 5-7 rows of hooked prickles; [tribe Cynodonteae; subtribe Traginae]

Key to Poaceae, Key E: grasses of tribe Andropogoneae (also including grasses also keyed in Keys B, C, and D)

Copy permalink to share | Check for keys that lead to this key

1 Leaves ovate-lanceolate, 2-10 cm long, 2.5-7× as long as wide; plants weak-stemmed annuals, branching, decumbent, rooting at the lower nodes; [exotic weeds].
  2 Leaves cordate-clasping at base; spikelets not paired, unaccompanied by a vestige
  2 Leaves tapering to a broadly cuneate base; spikelets paired (one of the pair sometimes vestigial)
1 Leaves lanceolate to linear, either longer or proportionately narrower; plants either perennial or coarse annuals with erect and mostly unbranched culms.
    3 Spikelets embedded in the thickened rachis (the inflorescence thus like an ear of corn), or fitting into grooves in the thickened rachis (the inflorescence thus cylindrical and resembling a rat's tail), or the pistillate inflorescences enclosed in a hard, bead-like, pearly-white, modified bract.
      4 Spikelets unisexual, with male and female spikelets in separate inflorescences or in different parts of the same inflorescence.
        5 Internode narrower than and more-or-less enclosed by the female spikelet
        5 Internode broader than and more-or-less enclosing the female spikelet.
          6 Racemes of mixed sex, female flowers below, and male above
          6 Racemes of single sex, the female inflorescences (“ears”) borne on axillary branches, the male inflorescences (“tassels”) terminal on the culm
 Zea
      4 Spikelets, or at least one of each pair, bisexual.
             7 Culms 2-45 cm tall; leaves 1-5 mm wide; plants perennial, obviously and prominently rhizomatous; lower glume with pectinate margins; [commonly naturalized turf grass and roadside weed]
             7 Culms 30-400 cm tall; leaves 2-25 mm wide; plants annual or perennial, cespitose or short-rhizomatous; lower glume winged or not, but not pectinate.
               8 Lower glumes of the sessile spikelets rough, rugose, pitted, tuberculate or alveolate between the keels
               8 Lower glumes of the sessile spikelets smooth or scabrous.
                 9 Pedicels at least partially fused to the rame axes
                 9 Pedicels appressed, but not fused, to the rame axes
                   10 Pedicellate spikelets 4-8 mm long
                   10 Pedicellate spikelets 1-3 mm long
    3 Spikelets not embedded or fitting into grooves in the rachis, the rachis slender (the spikelets visibly separate and often pedicelled).
                     11 Pedicelled spikelet similar to the sessile spikelet, both fertile.
                       12 Spikelets falling separately from the persistent rachis.
                          13 Panicle contracted, spikelike; glumes membranous
                          13 Panicle loose; glumes cartilaginous or coriaceous
                       12 Spikelets falling in pairs together with sections of the disarticulating rachis.
                            14 Spikelets awned with awns 10-26 mm long; anthers 2; [native, collectively common and widespread]
                            14 Spikelets unawned or with awns to 5.2 mm long; anthers 3; [exotic, rarely encountered]
                              15 Spikelets unawned
                              15 Spikelets with awns 4-5.2 mm long
                     11 Pedicelled spikelet differing from the sessile in shape and sex (sometimes represented only by a pedicel).
                                16 Spikelets awned, the awn 10-20 cm long.
                                  17 First glume lacking glands; panicle open, the branches 5-8 cm long
                                  17 First glume with a row of punctate, concave glands; panicle contracted, spikelike
                                16 Spikelets with or without awns, if awned the awns < 5 cm long.
                                    18 Inflorescence a panicle, the branches not subtended by sheaths.
                                       19 Pedicelled spikelet represented by pedicel only; apex of sheath bearing 2 auricles 1-10 mm long; [native]
                                       19 Pedicelled spikelet present, staminate; apex of sheath truncate; [exotic]
                                    18 Inflorescence of 1-13 digitate (whorled) racemes borne at the summit of a peduncle, the peduncle subtended by a raceme sheath.
                                         20 Racemes 1 per peduncle and raceme sheath
                                         20 Racemes 2-13 per peduncle and raceme sheath.
                                           21 Pedicels of the pedicelled (reduced or absent) spikelets terete or slightly flattened and grooved on one side only
                                           21 Pedicels of the pedicelled (reduced or absent) spikelets strongly flattened and with or without grooves on both sides.
                                             22 Rame internodes and pedicels with a translucent medial groove; pedicelled spikelets smaller than the sessile spikelets (or vestigial/absent)
                                             22 Rame internodes and pedicels without a translucent medial groove; pedicelled spikelets ca. the same size as sessile spikelets
Cite as...