Flora of North America species comparison

Dodecatheon hendersonii occurs from southern Vancouver Island in the coastal ranges to west-central California (as far as San Benito County) and is disjunct into the San Bernardino Mountains in southern California. To the east, the species is found on the Siskiyou Mountains and in the Sierra Nevada of California to Tulare County. A Macoun (s.n., DAO) specimen supposedly gathered at Yale, British Columbia, may be misattributed (K. I. Beamish 1955); all other known localities are from Vancouver Island.

Inasmuch as bulblets and mature capsules are rarely collected, it is difficult to clearly distinguish between var. hendersonii and var. hansenii. The former may be broadly characterized as plants bearing bulblets at anthesis with sparsely glandular scapes, pedicels, and, sometimes, calyces. The calyx of var. hendersonii is usually greenish with purple or reddish speckles. The most distinctive characteristics of this phase are a filament tube that is 1–2.5 mm wide and acute anther apices. It is found mainly along the coast from British Columbia to southern Oregon and in scattered locations in coastal California, with disjunct populations in the foothills of the central Sierra Nevada, and in the mountains of southern California. Variety hansenii is glabrous, lacks bulblets, and the calyx typically is green; it usually is found inland in the Siskiyou Mountains and the Sierra Nevada and scattered populations occur in the coastal ranges of northern California. The filaments in var. hansenii are broader, being tubes 1.5–4 mm wide, and anther apices are obtuse. Capsules of var. hendersonii are usually operculate; those of var. hansenii appear to be consistently valvate. The 2n = 66 plants appear to be primarily individuals that produce little or no pollen.

Adding to the complexity is the close association of var. hansenii with Dodecatheon clevelandii var. patulum. The latter, like var. hendersonii, is basically a diploid or a tetraploid (2n = 44, 88), rather than a hexaploid, and one would expect no crossing between the two. Nonetheless, H. J. Thompson (1953) reported finding sterile individuals where D. hendersonii var. hansenii and D. clevelandii var. patulum were in close association. These sterile individuals were morphologically similar to var. hansenii (and not intermediate between the two), and sterile individuals were fairly common in populations of var. hansenii where no other Dodecatheon were present. Although the three entities may be characterized (see table 5 in Thompson), Thompson concluded that assigning names to some populations was difficult and could be established “only by a detailed consideration and summation of all the characters.”

H. J. Thompson (1953) recognized Dodecatheon hansenii; A. F. Cholewa and D. M. Henderson (1993) accepted only D. hendersonii. In their molecular study, A. R. Mast et al. (2004) considered the two entities distinct, albeit closely related, species. It is possible that var. hansenii had a hybrid origin involving var. hendersonii and D. clevelandii var. patulum, and backcrossing with var. hendersonii resulting in a series of morphological features that allies the hansenii phase more to D. hendersonii than to D. clevelandii. More study is needed, especially in areas where the two appear to have overlapping ranges in the Bay Area and Sierra Nevada foothills of California.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera 20, species ca. 600 (5 genera, 52 species in the flora).

The largest genera in Primulaceae are Primula (ca. 500 species) and Androsace (ca. 100 species). No genera are endemic to the flora area; Dodecatheon and Douglasia have relatively few representatives elsewhere (northeastern Asia).

The family contains ornamental taxa, especially in Dodecatheon and Primula. Primula can cause dermatitis. Some taxa are pollinated by insects; selfing also occurs. Seeds are dispersed by gravity, water, wind, or ants (Primula; B. Ståhl and A. A. Anderberg 2004).

As typically described (e.g., A. Cronquist 1981; V. H. Heywood 1978), Primulaceae were clearly polyphyletic, closely related to Myrsinaceae and Theophrastaceae. M. Källersjö et al. (2000) and B. Ståhl and A. A. Anderberg (2004) removed the nonrosette terrestrial members from Primulaceae in the broad sense and placed them in the Myrsinaceae, which are further distinguished by leaves and calyx often dotted with yellow or dark streaks, flowers with relatively shorter corolla tubes, seeds immersed in placentae, and wood devoid of rays or with multiseriate rays only. Maesa, consisting entirely of trees found in the Eastern Hemisphere tropics, also has semi-inferior ovaries, pedicels with two bracts, and wood with both uniseriate and multiseriate rays; it, too, was removed from Primulaceae/Myrsinaceae and placed in its own family (Källersjö et al.). The families Primulaceae in the narrow sense, Myrsinaceae, Theophrastaceae (including Samolaceae), and Maesaceae then form a monophyletic clade within Ericales (P. F. Stevens, http://www.mobot.org/MOBOT/research/APweb/), sharing some features, most notably flowers with sympetalous corollas, stamens in a single series and opposite the petals, free-central placentation, bitegmic, tenuinucellate ovules, and plants generally with tannins and saponins.

Additional evidence (L. Martins et al. 2003) indicates that Androsace and Primula may not be monophyletic; more work is needed to resolve these issues. The work of M. Källersjö et al. (2000) showed that Douglasia should remain separate from Androsace, and Dodecatheon should remain separate from Primula, although Dodecatheon clearly is derived from Primula subg. Auriculastrum. Alternative views suggesting more inclusive concepts of Primula and Androsace have been offered by I. Trift et al. (2002), A. R. Mast et al. (2004), and G. M. Schneeweiss et al. (2004). The phylogenetic position of Cyclamen, a scapose taxon currently included in Myrsinaceae, has not been resolved. Our understanding of Primulaceae is still in flux, and future taxonomic realignments at the familial and generic levels are to be expected.

(Discussion copyrighted by Flora of North America; reprinted with permission.)