Annual Salt-marsh Aster

Annual Salt-marsh Aster
Annual Salt-marsh Aster. Symphyotrichum subulatum, formerly Aster subulatum.
Asteraceae, the daisy, sunflower, or composite family.

Plant: Erect, branching, somewhat delicate stems, sometimes purple-tinged, 1'-3' high, hairless, with loose terminal clusters of very small, violet to whitish, daisy-like flower heads. Annual.
Flowers: Very small, violet to whitish flower heads, generally 1/4" or less, generally with about 20 rays, and yellow centers, in open panicles. Not opening as widely as most asters.
Leaves: Alternate, linear, grass-like, sessile, smooth with smooth margins, fairly sparse, with most axils bearing a branch. Some small, bract-like leaves near flower heads.
Fruit: A globular head of silky-haired achenes
Blooming: September-October Plants bloom only for a short time compared to most asters.
Habitat: Mostly in or near salt marshes or brackish areas. Sometimes found in roadsides areas that retain salt from winter snow and ice treatment.

Comments: One of two similar salt-marsh asters in our area; the other is Perennial Salt-marsh Aster S. tenuifolium, which has slightly larger flowers, greener stems, and is more restricted to near-coastal regions. The plants pictured here were growing under a highway bridge in Rochester NY, where presumably, road salt tended to persist, being sprayed off the bridge by traffic, but somewhat protected from rain by the structure. Salt-tolerant species would likely have an advantage in this area.

Where to find it: Under the high I-390 connecting bridge.