Symphyotrichum subulatum
Symphyotrichum falcatum
annual saltmarsh American-aster, annual saltmarsh aster, annual saltmarsh or eastern annual saltmarsh aster, aster subulé, eastern annual saltmarsh aster, Southwestern annual saltmarsh aster
Lindley's aster, little gray aster, little grey aster, western heath or white prairie aster, white prairie aster
1, erect (often with purple or purplish brown areas), glabrous or glabrate, sometimes strigillose in leaf axils.
1–5+, ascending to erect (grayish brown to brown), moderately to densely hairy.
thin (green to dark green), margins often strigilloso-ciliolate, faces glabrous;
basal withering by flowering, long-petiolate (petiole bases sheathing), sparsely ciliate, blades ovate to oblanceolate, 10–90 × 6–14 mm, bases attenuate to cuneate, rounded, margins entire or serrulate or crenulate, apices rounded, obtuse, or acute;
proximal cauline withering by flowering, petiolate, subpetiolate, or sessile, blades narrowly lanceolate or subulate, 20–100(–200) × 1.5–10(–20) mm, bases attenuate, margins subentire, entire, or serrulate, apices acute to acuminate;
distal sessile, blades narrowly lanceolate to subulate, 5–113 × 0.5–5.5 mm, apices acuminate.
(light grayish green) firm, margins entire, strigose, apices ± spine-tipped;
basal withering by flowering, sessile, blades oblanceolate, 10–40 × 3–10 mm, bases attenuate, margins usually entire, rarely remotely serrate, scabrous, apices acute to obtuse, rounded to mucronulate-spinose, faces glabrate to moderately strigose;
proximal cauline sessile, blades linear oblanceolate to oblong, 10–40(–60) × 1.5–4(–7) mm, reduced distally, bases cuneate, margins entire, coarsely ciliate, apices acute or obtuse, faces sparsely to densely appressed hispido-strigose;
distal sessile, blades linear-oblong to linear-lanceolate, 25–45 × 2–3 mm, bases cuneate, margins entire, apices acute, faces moderately to densely strigose.
(0.2–)0.5–4 cm, bracts 4–8(–17).
0.2–4 cm, densely hairy, bracts 1–3+, linear to lanceolate, densely hairy.
cylindric to turbinate, 5–7(–8.2) mm.
campanulate, (4.5–)5–8 mm.
16–30(–54) in 1–3 series;
corollas white, pink, or lavender, laminae 1.3–7 × 0.2–1.3 mm.
(15–)20–35;
corollas usually white, sometimes blue or pink, laminae (8–)18–30 × 1.1–1.4 mm.
4–10(–13);
corollas yello, sometimes tinged with purple, 3.4–5.2 mm, throats narrowly funnelform, lobes ± spreading to erect, narrowly triangular, 0.3–0.7 mm, glabrous.
(8–)18–30;
corollas yellow becoming brown, 2–2.5 mm, lobes triangular, 0.7–1.2 mm, glabrous.
in 3–5 series, broadly or narrowly lanceolate to subulate, unequal, bases indurate, margins hyaline, often purple-tinged, entire, green zones lanceolate (usually narrow, sometimes broad and covering most of distal portion), apices acute, faces glabrous.
in 3–4 series, outer oblanceolate to spatulate (1.5–2 mm), inner linear-lanceolate (3–4 mm), unequal, bases (whitish to tan) ± indurate in basal 1/2–3/4, margins hyaline, scabrous proximally, green zones diamond-shaped, in distal 1/4–1/2, apices (outer) acute to obtuse, clear spine-tipped, spreading to reflexed, (inner) acuminate to attenuate, faces sparsely to moderately hispid-strigose.
(10–) 30–100(–150), in open, diffuse, paniculiform arrays.
[(1–)10–200+] in racemiform to diffuse-paniculiform arrays (1–10+ per branch, usually not crowded).
light brown to purple, narrowly obovoid to fusiform, sometimes ± compressed, (1.2–)1.5–2.7(–3) mm, 5-nerved, faces sparsely strigillose;
pappi white, (3–)3.5–5.5 mm.
dark brown, obovoid, not compressed, 2–2.5 mm, faint-nerved, faces densely strigose;
pappi whitish, 4.5–6 mm.
Symphyotrichum subulatum
Symphyotrichum falcatum
Varieties 5 (5 in the flora).
Five varieties of Symphyotrichum subulatum are recognized for North America based on differences in chromosome number, ray lamina color and size, array shapes, number of series of ray florets, number of disc and ray florets, and other, more cryptic characters (S. D. Sundberg 2004). These varieties were treated as species by G. L. Nesom (1994b, 2005d). Variety ligulatum is apparently an obligate outcrosser and is the least variable variety (Sundberg). Other varieties are self-compatible, which could facilitate the fixation of mutations in populations.
The five varieties are nearly entirely allopatric, and intermediates between pairs of varieties are not uncommon where they approach one another. Populations that are intermediate in ray lamina size between vars. ligulatum and parviflorum are widespread in southern Texas, New Mexico, Arizona, and northern Mexico. Intermediates between vars. elongatum and parviflorum and between vars. elongatum and subulatum occur in Florida. Despite these observations, hybridization experiments and chromosome number differences suggest that the varieties are mostly reproductively isolated (S. D. Sundberg 1986, 2004).
In older floras the name Aster exilis Elliott has been applied to Symphyotrichum subulatum vars. ligulatum and parviflorum. The status of this name is uncertain; the type specimen has been lost and the description of the plant is inadequate for determining the taxon to which the name should be applied (G. L. Nesom 1994b; S. D. Sundberg 2004).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (2 in the flora).
Symphyotrichum falcatum is introduced in Ontario and Illinois. It may closely resemble S. ericoides, which has smaller heads with fewer florets in denser arrays. The two can be difficult to distinguish on the Great Plains. A. G. Jones (1978) recognized two subspecies of S. falcatum, one with two varieties. Those two subspecies are treated as varieties here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Ray laminae lavender to blue, (3.5–)4.5–7 × 0.9–1.3 mm, drying in 3–5 coils; ray florets in 1 series; disc florets (20–)33–50 (sc United States) | var. ligulatum |
1. Ray laminae white to pink or lavender, 1.3–3.5(–4.2) × 0.2–0.6 mm, drying in (0–)1–3(–4) coils; ray florets in 1–3 series; disc florets 3–23 | → 2 |
2. Ray laminae pink to lavender, (2–)2.5–3.5(–4.2) × 0.3–0.6 mm, drying in 2–3(–4) coils; disc florets 11–23 (Florida, West Indies) | var. elongatum |
2. Ray laminae usually white, rarely pink or lavender, 1.3–3 × 0.2–0.5 mm, drying in 1 coil or curling; disc florets (3–)4–15 | → 3 |
3. Ray laminae longer than pappi; phyllaries 30–42; pappi 3.5–3.8(–4.2) mm; w United States | var. parviflorum |
3. Ray laminae shorter to slightly longer than pappi; phyllaries 18–30; pappi 3.5–5.5 mm; e and se United States | → 4 |
4. Green zones of phyllaries narrowly to broadly lanceolate, extending phyllary length; ray laminae 0.2–0.5 mm wide; disc florets 3.8–4.6(–4.9) mm; salt marshes, e North America and Gulf Coast | var. subulatum |
4. Green zones of phyllaries broadly lanceolate, nearly absent from proximal portion; ray laminae 0.2–0.3 mm wide; disc florets 3.2–4.1 mm; adventive, s United States | var. squamatum |
1. Plants cespitose, 1–5(–10)-stemmed, usually sparsely appressed-strigose, with cormoid caudices; new shoots developing near the bases of old stems; peduncles long, slender, bracts 1–5; phyllaries subequal (outer longest and foliaceous), apices not strongly squarrose | var. falcatum |
1. Plants colonial, usually densely hairy, rhizomes entangled, usually 1-stemmed, sometimes clumped; new shoots developing at ends of elongated rhizomes; peduncles stout, bracts 2–10+; phyllaries ± unequal, apices strongly squarrose | var. commutatum |
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