Fragrant popcornflower (Plagiobothrys figuratus) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

Scientific name:

Plagiobothrys figuratus (Piper) Johnst. ex M.E. Peck

Synonyms:

  • Plagiobothrys hirtus var. figuratus (Piper) Johnst.
  • Allocarya dichotoma Brand
  • Allocarya figurata Piper

Common names:

fragrant popcornflower, rough popcornflower (a name also used, but more appropriately applied to P. hirtus)

Family:

Boraginaceae, borage family

Major plant group:

Eudicot flowering plant

Taxonomists have debated the correct placement of species within the genera Allocarya and Plagiobothrys since the early 1900s. Hitchcock et al. (1959) follow Johnston’s treatment (Johnston 1923) using minor variations in the nutlets as the basis for establishing this species within Plagiobothrys. The only taxon recognized in Canada for Plagiobothrys figuratus is ssp. figuratus as accepted in recent treatments of the genus (e.g., Douglas et al. 1998, Kartesz 1999). However, the overall monophyly of this genus remains in doubt and a revision of the group is currently underway (Dellavalle-Sanvictores 2000). Hitchcock et al. (1959) note that Allocarya scouleri (= P. scouleri) has been erroneously applied to Plagiobothrys figuratus.

A second subspecies, endemic to Oregon, is also recognized: Plagiobothrys figuratus ssp. corallicarpus (Piper) Chambers (NatureServe 2005).

Morphological description

Fragrant popcornflower is a hairy, prostrate to erect annual herb with a single or branched stem and fibrous roots. Plants range from 10-45 cm high. The leaves are found mainly on the stems, with the lower 3-4 pairs opposite and the upper leaves alternate. The lower leaves are linear and 4-12 cm long while the upper leaves are linear to lance-shaped and range from 1-5 cm long. The inflorescence is composed of several narrow, coiled spikes that elongate as they mature. The flowers are showy, 5-10 mm wide with white petals that are fused at the base into a tube, and a yellow eye (Figure 1). The mature sepals are densely hairy, often with reddish-brown hairs, and are 3-4 mm long. Each flower produces 4 egg-shaped, wrinkled nutlets (some of which may abort before maturing) that vary in length from 1.2-1.7 mm (Hitchcock et al. 1959, Douglas et al. 1998).

In Canada, fragrant popcornflower may be confused with Scouler’s popcornflower (Plagiobothrys scouleri), which grows in similar habitats but has far smaller flowers, and with slender popcornflower (P. tenellus), which, however, grows in different habitats (mesic to dry meadows and coastal bluffs). The latter species also lacks opposite leaves. Common cryptantha (Cryptantha intermedia var. grandiflora) is another similar species that could lead to misidentifications, but it also occurs in different habitats such as dry to mesic disturbed areas in lowland and montane regions (Hitchcock et al. 1959, Douglas et al. 1998).

Figure 1. Fragrant popcornflower. Photo courtesy of H. Roemer.

image of Figure 1.Fragrant popcornflower.  Photo courtesy of H. Roemer

Genetic description

Although no information is available on the population genetics of fragrant popcornflower, recent studies of the narrow endemic Plagiobothrys hirtus (rough popcornflower) at various locations in the U.S. have revealed distinct morphological and phenological differences that indicate the existence of significant genetic variation among populations at a small geographic scale (Amsberry 2001, USFWS 2003).

Designatable units

A single designatable unit is recognized based on the occurrence of one extant population in 2005.

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