Pink sand-verbena (Abronia umbellata) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

Scientific name:

Abronia umbellata Lam. ssp. breviflora (Standley) Munz

Synonyms:

  • Abronia umbellata Lam. ssp. acutalata (Standley) Tillett
  • Abronia umbellata Lam. var. acutalata (Standley) C.L. Hitchcock
  • Abronia acutalata Standley
  • Abronia breviflora Standley

Common Name:

Pink Sand-verbena

Family:

Nyctaginaceae, Four O’clock family

Major Plant Group:

Angiosperm (Dicot flowering plant)

Description

Pink sand-verbena, Abronia umbellata ssp. breviflora is a member of a genus of 25 species of western North America (Spellenberg 1993). Two species occur in British Columbia and three in Canada (Scoggan 1978; Douglas et al. 1999, 2002a, b).

The A. umbellata Lam. complex has received markedly different taxonomic treatments over the years. In 1791, J. B. P. A. Lamarck, a French botanist described A. umbellata from seed collected at Monterey on the central California coast. Later, in a monographic treatment of the subtribe Abroniinae, Standley (1909) split the A. umbellata complex and described four additional species on the west coast. In contrast, Ferris (1944), in Abrams’ Illustrated Flora of the Pacific States, concluded that the Pacific Coast material was best treated within a single species. Munz (1959), in his Flora of California, recognized all five of Standley’s taxa for coastal California but treated them at the subspecies level. In 1964, C.L. Hitchcock, in the Vascular Plants of the Pacific Northwest (Hitchcock 1964) recognized only two taxa for the Pacific westcoast: Abronia umbellata var. umbellata (ranging from central Califonia south to Mexico and var. acutalata (Standl.) C.L. Hitchc ranging from central California north to British Columbia). Subsequently, Tillett (1967) conducted a detailed investigation into the westcoast A. umbellata complex that resulted in his recognition of three subspecies: ssp. acutalata (Standl.) Till. in Washington and British Columbia, ssp. breviflora (Standl.) Munz in Oregon and northern California and ssp. umbellata from central California to Mexico. Spellenberg (1993) treating the genus for The Jepson manual: Higher plants of California and Kaye (1995, 1999), working on the Oregon coast, followed the concept of Hitchcock (1964) but choose to recognize the northern taxon as ssp. brevifolia. In contrast, when material from British Columbia was recollected, after a hiatus of 73 years (Douglas 2001), measurements from a limited number of achenes lead Douglas (2002a, b) to conclude that the concept of Tillett (1967), was the most appropriate and that the northern material should be recognised as ssp. acutalata.

More recently, a study of chloroplast DNA found no difference between British Columbia and Oregon populations (Kaye 2002). Kaye (2002) also conducted a morphometric analysis of British Columbia and Oregon from greenhouse grown material and found only slight differences between them. As a result of the latter investigations, the British Columbia taxon should now be recognized as ssp. breviflora.

Only a single infraspecific taxon of Abronia umbellata is present in Canada. In this report pink sand-verbena is referred to simply as Abronia umbellatarather than by its more precise name of Abronia umbellata ssp. breviflora.

Abronia umbellata is a perennial herb from a thick, deep taproot (Figure 1; Douglas 2002a, b). Canadian plants have trailing stems up to 1.5 m long with short braches and opposite, thick, fleshy, densely glandular leaves. The leaves are lanceolate to narrowly egg-shaped, 2-6 cm long, 0.8-3.5 mm wide with stalks 2.5-7 cm long. The many-flowered, rounded heads occur on stout, 2-4 cm stalks. The flowers consist of a 6-8 mm long, greenish to pinkish perianth tubes that flare into pink, 5-lobed limbs 5-6 mm wide. The fruits consist of 10-12 mm achenes that are prominently 3- or 4-winged. The wings of the achenes are wider than the achenes. Each achene has a single, brown, seed approximately 1.5 mm wide and 3 mm long.

Figure 1. Illustration of Abronia umbellata (ssp. breviflora). (Line drawing from Hitchcock 1964, by permission).

Figure 1. Illustration of Abronia umbellata (ssp. breviflora). (Line drawing from Hitchcock 1964, by permission).

Abronia umbellata could be confused with its relative, Abronia latifoliaFootnote1, especially if the plants are immature or not in flower. The latter species has yellow flowers, broader, egg- to kidney-shaped leaves and achenes with wings narrower than the fruit bodies (Douglas 1999, 2002b).

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