Coast Jointweed

Appearance

Flowers in the axils of short bracts, all but the lowermost bracts less than twice as long as the flowers, the inflorescence thus appearing to be a remotely flowered slender spike; plants stiffly erect with leaves mostly linear (rarely all nearly elliptic) and very sharply acute. Pedicels with a swollen joint near the middle (but not far above the sheathing ocreolae); leaves not over 1 (–1.1) mm wide.

Herbs, annual, synoecious, 1-5 dm. Stems erect, branched proximally and distally, glabrous. Leaves persistent or fugaceous; ocrea margins not ciliate; blade linear to narrowly clavate, (1.5-)5-20(-35) × 0.4-1.2 mm, base barely tapered, margins not hyaline, apex obtuse, glabrous. Inflorescences (13-)20-33(-40) mm; ocreola encircling rachis, only the base adnate to rachis, apex acute. Pedicels spreading in anthesis, reflexed in fruit, 0.9-2.1 mm, longer than subtending ocreola. Flowers bisexual; outer tepals loosely appressed in anthesis and fruit, pink to white, occasionally red, distal portion of midrib often inconspicuously greenish, elliptic to obovate, 1.3-2.3 mm in flower, margins entire to erose; inner tepals loosely appressed in anthesis and fruit, white to pink, occasionally red, elliptic, 1.3-2.3 mm in anthesis, margins mostly entire; filaments dimorphic; anthers yellow or pink; styles and stigmas ca. 0.1 mm in anthesis. Achenes included or exserted, reddish brown, 3(-4)-gonous, 2-2.8 × 1-1.3 mm, shiny, smooth. 2n = 32.

Naming

Polygonella articulata (Linnaeus) Meisner
Delopyrum articulatum (L.) Small
Polygonum articulatum L.

Etymology: Polygonella: diminutive of Polygonum; from poly for "many" and gonu for knee, referring to many joints.

Distribution

Ont., P.E.I., Que.; Conn., Del., Ga., Ill., Ind., Iowa, Maine, Md., Mass., Mich., Minn., N.H., N.J., N.Y., N.C., Pa., R.I., Wis., Vt., Va.

Habitat

Pine barrens, sandhills, and sandy sites along lake shores, beaches, river banks, roadsides, and railroads.

Reproduction

By seeds. The plant is an annual.