Monographs Details: Hackelia setosa (Piper) I.M.Johnst.
Authority: Gentry, Johnnie L. & Carr, Robert L. 1976. A revision of the genus Hackelia (Boraginaceae) in North America north of Mexico. Mem. New York Bot. Gard. 26: 121-227.
Description:Species Description - Perennial, (3-)4-6 dm tall; stems few from an often much branched, moderately slender, woody caudex, erect or somewhat ascending, antrorsely strigose in the upper parts of the inflorescence, otherwise mostly spreading, the hairs curved downward near the stem base. Radical leaves often very many, 9-17(-23) cm long, 9-17(-30) mm wide, narrowly elliptic, petiolate and narrowly winged for ca. 1/2 their length, uniformly spreading hirsute-sericeous or the trichomes less commonly subappressed; cauline leaves mostly sessile, the lowermost 5-8 cm long, 4-8 mm wide, linear or narrowly oblanceolate, reducing upwards, becoming lanceolate or narrowly elliptic just below the inflorescence. Pedicel 6-9 mm long in fruit. Calyx lobes 2.5-3.5 mm long, linear-lanceolate. Corolla limb blue with a whitish throat, 8-13 mm wide; tube ca. 2 mm long. Fornices with appendages minutely papillate-puberulent, emarginate, longer than broad. Anthers 0.8-0.9 mm long. Nutlets 3.2-3.7 mm long, ovate; dorsal surface very rough, rugose, covered with very minute, stiff hairs, the intramarginal prickles 9-13, distinct, the prominent marginal prickles distinct nearly to the base, 1.5-2.0 mm long, these alternating with 1-3 much shorter glochidia. Chromosome number 2n = 48.
Distribution and Ecology -
Discussion:Lappula setosa Piper, Bull. Torrey Club 29: 544. 1902.
Type. CALIFORNIA. Sierra Valley, July 1883, Lemmon s.n. (holotype, CAS!).
A very striking plant easily distinguished from other Hackelia species of Northern California by its corolla color and shape, by the largely spreading setose hairs of the stem and leaves; and by the size, form, and texture of the nutlets. These characters, although variable, apparently are reliable throughout the known range of the taxon.
The type as established by Piper differs from most plants we have seen in having stouter and more spreading pubescence. Much of the pubescence of the inflorescence is spreading and only curved upwards, not antrorsely strigose. The nutlets of the type have a fairly broad flange rather than the narrow one that is common throughout the northern part of the range. These morphological features, which may be common in the southern part of the range (see Knight et al. and Carruth 26087 and 26088 at CAS) may, upon further investigation, lead to the recognition of subspecific categories. As was discussed briefly before, there is a great need for extensive field work in this Northern California area. A number of the distinctive specimens found here quite probably represent undescribed taxa or cases of introgression.
Morphologically and in habit Hackelia setosa aligns itself most closely with H. diffusa var diffusa whose range lies to the north. Indeed, there are few, if any, clear-cut morphological features that separate these two taxa. Hackelia setosa tends to have some fusion of the marginal prickles, whereas H. diffusa has these prickles distinct to their base. The cauline leaves of H. setosa are smaller and tend to be somewhat more bristly, and the radical leaves are obtuse or broadly acute as opposed to mostly sharply acute in H. diffusa var diffusa.
Distribution:United States of America North America