E-Flora BC: Electronic Atlas of the Flora of British Columbia

This is the most widespread and variable species of Dodecatheon in B.C., and the only member of the genus with multiple infraspecific taxa in the province. There is great variation in many morphological features in this species, much of which is environmentally induced, which can render some specimens difficult to place within the existing infraspecific framework. Fortunately, however, the three varieties overlap in distribution only locally (var. cusickii and var. pulchellum overlap in southeastern B.C.) and, where they overlap, the vast majority of specimens maintain their distinguishing characteristics and are easily identified. The three varieties that are recognized for B.C. are distinguished as follows:

1a. Plants extensively glandular-pubescent on the leaves, scapes, involucral bracts, pedicels, and calyces; plants of sc and se BC…...………………. …………………………………..……….........................................................................var. cusickii (Greene) Reveal

1b. Plants usually glabrous (never glandular-pubescent); plants of both coastal and interior BC........................................................................…2

2a. Pollen sacs entirely dark reddish-purple; plants restricted to se and (rarely) sc B.C…...………...……….……...…...……..var. pulchellum

2b. Pollen sacs whitish to yellowish, at least towards the apex; plants strictly coastal..……………….….var. macrocarpum (A.Gray) Reveal

The diploid var. cusickii (= D. cusickii, D. puberulum) is the common and widespread variety of dry climates in the southern interior, where it is most abundant in the south-central interior. It is less frequent in southeastern B.C., where it occurs alongside the similarly diploid var. pulchellum. It tends to occur on drier upland habitats than var. pulchellum, such as grasslands and sagebrush steppe, although it typically occurs in moist draws or meadows within these dry habitats. It is most common at low elevations but also extends locally into subalpine and alpine habitats, especially along the eastern flanks of the Coast-Cascade Ranges. It is usually easily distinguished from the other varieties by its extensive, usually dense glandular pubescence throughout, especially on the upper scape, involucral bracts, pedicels, and calyces. Some populations (e.g., Mount Kobau) have this glandular pubescence greatly reduced, however, so the presence of gland-bearing hairs may be difficult to determine without close inspection on some specimens. It is unclear if such populations are merely inconspicuously glandular forms of var. cusickii or if there is some introgression (either current or historical) with var. pulchellum. The glabrous var. pulchellum is locally frequent in southeastern B.C. but becomes rare and scattered in south-central B.C. It is predominately a species of low elevation habitats throughout its distribution, although occasional subalpine or alpine populations of small, depauperate plants occur locally. These alpine forms have been named var. watsonii by some authors but, as it occurs somewhat sporadically within the range of var. pulchellum, and appears to differ only in overall size, most recent authors are hesitant to recognize it; it is presumably a response to the extreme growing conditions at high elevations. The polyploid (usually tetraploid) var. macrocarpum (= D. pulchellum ssp. alaskanum, D. pulchellum ssp. superbum) ranges along the coast from Alaska to Oregon, and it can be difficult to distinguish morphologically from the var. pulchellum due to variation in the colour of the pollen sacs in both varieties; herbarium specimens can be particularly hard to identify as the dark pollen sacs of var. pulchellum tend to fade and become yellowish (thus approaching var. macrocarpum) with age. Fortunately, these two varieties occupy different geographic ranges (var. macrocarpum along the coast, var. pulchellum in the southeastern [rarely south-central] interior) and never come into contact, so any specimens of known origin should be easily placed into one or the other variety. A population of small, depauperate plants on Mount Arrowsmith on southern Vancouver Island has generally been attributed to var. pulchellum or var. watsonii by most authors; however, as this population is tetraploid rather than diploid (Suttill and Allen 1992) and is considerably disjunct from any other populations of var. pulchellum, it is best considered a depauperate alpine population of var. macrocarpum. Variety macrocarpum is otherwise generally associated with low elevation habitats, especially those along the immediate seacoast such as seaside meadows, estuaries, and coastal headlands.

Source: The Vascular Flora of British Columbia, draft 2014
Author: Jamie Fenneman