Grand coulee owl-clover (Orthocarpus barbatus) COSEWIC assessment and status report: chapter 5

Species information

COSEWIC Status Report
on the
Grand Coulee Owl-clover
Orthocarpus barbatus
in Canada
2005

Name and classification

Scientific name:
Orthocarpus barbatus Cotton Footnote 4
Common name:
Grand Coulee Owl-clover
Family:
Orobanchaceae (broomrape family)
Major plant group:
Dicot flowering plant


Keck (1927) recognized 25 annual species of Orthocarpus within the subtribe Castillejinae (family Scrophulariaceae). Many of these species have now been placed within Castilleja or Triphysaria, leaving nine species in Orthocarpus as it is now recognized (Chuang and Heckard 1991). Five of these species occur in British Columbia and Canada (Pojar 2000).

Orthocarpus was considered part of the family Scrophulariaceae until recent work determined that all parasitic Scrophulariaceae should be separated into the family Orobanchaceae (Olmstead et al., 2001).

Description

Orthocarpus barbatus is a yellowish annual herb (Figure 1) from an erect stem 8-25 cm tall, slender, simple or with erect branches above (Pojar 2000). The plant has a mixture of long and short hairs and is tinged yellowish-green. The leaves are alternate, stalkless, linear to narrowly lanceolate, spreading-hairy and 2-4 cm long. The leaves are entire or deeply cleft into 3 to 5 long, narrow lobes. The flowers are grouped in a dense, prominently bracted terminal spike. The bracts are green or yellowish-green, 3 to 5 cleft into narrow lobes. The flowers are yellow and 10-12 mm long, exerted from the bracts and tube-shaped. The calyces are tube-shaped. The fruits are capsules that are elliptical in shape and contain several seeds with tight-fitting, netted coats.


Figure 1. Illustration of Orthocarpus barbatus

Illustration of Orthocarpus barbatus

Plant habit (left), flower (top right) and characteristic bract subtending the flowers (Line drawing by Lora May Richards in Pojar 2000; by permission).


Two other yellow-flowered species of Orthocarpus, O. luteus and O. tenuifolius, occur in the same area as O. barbatus in south-central British Columbia. They may be distinguished by their inflorescence bracts, 3 to 5 cleft into long narrow lobes in O. barbatus versus 3-lobed bracts with shorter lobes in O. luteus and O. tenuifolius.

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