4.
Grindelia squarrosa
(Pursh) Dunal, Mém. Mus. Hist. Nat. 5: 50. 1819.
Donia squarrosa
Pursh, Fl. Amer. Sept. 2: 559. 1813;
Grindelia aphanactis
Rydberg;
G. nuda
Alph. Wood;
G. nuda
var.
aphanactis
(Rydberg) G. L. Nesom;
G. serrulata
Rydberg;
G. squarrosa
var.
nuda
(Alph. Wood) A. Gray;
G. squarrosa
var.
serrulata
(Rydberg) Steyermark
Biennials, perennials, or subshrubs
(perhaps flowering first year, usually short-lived), (10—)40—100 cm.
Stems
erect, usually whitish or stramineous, sometimes reddish or grayish, glabrous.
Cauline leaf blades
oval, ovate, obovate, or oblong to spatulate, oblanceolate, lanceolate, or linear, (10—)15—70 mm, lengths 2—5(—10) times widths, bases ± clasping, margins usually crenate to serrate (teeth mostly 3—6+ per cm, rounded to obtuse, resin-tipped), rarely entire, apices obtuse to acute, faces glabrous, strongly gland-dotted.
Heads
usually in open to crowded, corymbiform arrays, rarely borne singly.
Involucres
broadly urceolate to hemispheric or globose, 6—11 × 8—20+ mm.
Phyllaries
in 5—6 series, reflexed to spreading or appressed, filiform or linear to lance-linear or lance-subulate, apices usually looped to hooked, sometimes recurved to nearly straight, subterete to subulate, moderately to strongly resinous.
Ray florets
0 or (12—)24—36(—40); laminae 8—14 mm.
Cypselae
whitish, stramineous, brown, or gray, 1.5—4.5 mm, apices smooth, coronate, or knobby, faces smooth, striate, or ± furrowed;
pappi
of 2—3(—8), straight or contorted to curled, smooth or barbellulate to barbellate, subulate scales or setiform awns 2.5—5.5 mm, shorter than disc corollas.
2
n
= 12.
Flowering Jul—Sep(—Oct). Disturbed sites, plains, hills, roadsides, along streams, sands, clays, and subalkaline soils; (10—)200—2900 m; Alta., B.C., Man., Ont., Que., Sask.; Ariz., Ark., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.Dak., Tex., Utah, Vt., Va., Wash., Wis., Wyo.; Mexico (Chihuahua); introduced in Asia (Ukraine).
Grindelia squarrosa
is probably native to the Great Plains and, perhaps, Rocky Mountain areas; it is widely introduced in other areas. Some plants are intermediate between it and
G. hirsutula
(i.e., between
G. squarrosa
and
G. perennis
, which has been treated as a variety of
G. squarrosa
). Plants of
G. squarrosa
with relatively narrow leaf blades (lengths mostly 5—8 times widths), mostly from the western part of the range of the species, have been treated as
G. squarrosa
var.
serrulata
. G. L. Nesom (1990i) and others have treated discoid plants included here in
G. squarrosa
as distinct (as
G. aphanactis, G. nuda
, and/or
G. nuda
vars.
aphanactis
and
nuda
); Nesom reported cypselae to be dimorphic in heads of radiate plants and monomorphic in discoid plants and noted that populations with discoid plants occur mostly south and west of populations with radiate plants. According to Nesom, plants of
G. nuda
with stems usually reddish (versus sometimes greenish), lengths of blades of mid-cauline leaves 4—10 (versus 1.5—4) times widths, and cypselae ± deeply furrowed (versus striate to shallowly furrowed) should be called
G. nuda
var.
aphanactis
.
Hybrids between
Grindelia squarrosa
(
nuda
) and
G. arizonica
have been recorded from Arizona and New Mexico.
