Aconogonon alaskanum

(Small) Soják

Preslia 46: 150. 1974

Common names: Alaska wild-rhubarb
Synonyms: Polygonum alaskanum (Small) W. Wight ex Harshberger Polygonum alpinum subsp. alaskanum (Small) S. L. Welsh
Basionyms: Polygonum alpinum var. alaskanum Small
Treatment appears in FNA Volume 5. Treatment on page 598.
Plants (30–)50–150(–200) cm. Stems erect, glabrous or densely and retrorsely pubescent. Leaves: ocrea reddish brown, funnelform, 1–2.2 cm, margins oblique, glabrous or pilose; petiole 0.8–3.5(–4) mm; blade narrowly lanceolate to ovate, 5–20 × 2–8 cm, not subcoriaceous, base truncate or obtuse to subcordate, margins sometimes irregularly undulate, ciliate or, rarely, glabrous, apex acuminate, faces not glaucous, glabrous or pubescent. Inflorescences terminal, sometimes also axillary, paniclelike; peduncle 0–4 cm, glabrous or pubescent. Pedicels 0.5–0.1 mm. Flowers 2–4 per ocreate fascicle, all flowers with stamens well developed; perianth white or greenish white, 2–4 mm; tepals dimorphic, rarely slightly so, ovate, apex obtuse; anthers yellow to pink. Achenes included or exserted, tan to grayish brown, not beaked distally, 2.6–3.8 × 2–3 mm, shiny, faces usually not concave. 2n = 20.

Distribution

V5 1215-distribution-map.gif

nw North America, Europe (e Russia).

Discussion

Varieties 2 (2 in the flora).

Aconogonon alaskanum has been considered conspecific with the morphologically similar Eurasian A. alpinum (Allioni) Schur, but the taxa differ in leaf size and achene characters. Nomenclatural issues were clarified by J. T. Kartesz and K. N. Gandhi (1990) and K. L. Chambers (1992).

References

None.

Key

1 Leaf blades pubescent; stems usually densely and retrorsely pubescent Aconogonon alaskanum var. alaskanum
1 Leaf blades glabrous except for margins; stems mostly glabrous, rarely pubescent proximal to nodes Aconogonon alaskanum var. glabrescens