3. Phacelia gilioides Brand

Pl. 429 c, d; Map 1918

Plants relatively slender annuals. Stems 10–40 cm long, unbranched or few- to several-branched at the base and above, mostly strongly ascending from a sometimes spreading base, moderately pubescent with stiff, appressed or strongly ascending, nonglandular hairs toward the base, also with moderate to dense, fine, somewhat tangled, nonglandular hairs toward the tip. Basal leaves usually withered at flowering, the blade 1–3 cm long, elliptic to oblong in outline, pinnately compound or deeply lobed with 5–11 pinnae or lobes, these entire or occasionally with 1 or 2 lobes or coarse teeth (the terminal leaflet or lobe usually 3-lobed), the leaflets or lobes sharply to bluntly pointed or rounded at the tips, the surfaces sparsely to moderately pubescent with more or less appressed, stiff hairs. Stem leaves short-petiolate to sessile and usually clasping, the blade 0.8–5.0 cm long, progressively reduced toward the stem tip, the uppermost leaf blades usually 5 or 7(9)-lobed, the leaflets or lobes bluntly to more commonly sharply pointed at the tips, the terminal lobe of at least the uppermost leaf (immediately below the lowermost flower) truncate to slightly angled or tapered at the base, the pubescence similar to that of the basal leaves. Inflorescences with 8–25 flowers, the axis and flower stalks pubescent with dense, short, ascending to appressed hairs and sparse to moderate, longer, stiff, spreading hairs, the stalks ascending to spreading at fruiting. Calyces 4–8 mm long, the lobes with the margins and surfaces pubescent with longer and shorter hairs. Corollas 5–8 mm long, broadly bell-shaped, purple to bluish purple, the margins coarsely and irregularly toothed to fringed, the outer surface finely hairy, especially along the midvein and toward the tip. Stamens not or very slightly exserted, the filaments 4–7 mm long, densely hairy for most of their length. Ovary with mostly 8 ovules. Style branched to less than or about the midpoint. Fruits 3–4 mm long, the surface not appearing swollen, mostly 6–8-seeded. Seeds 1.5–2.0 mm long, ovoid-angled, finely ridged and/or pitted, dark brown. 2n=18. April–June.

Scattered, mostly south of the Missouri River, most commonly in the Ozark Division (Illinois, Missouri, Arkansas, Kansas, and Oklahoma). Bottomland forests, mesic upland forests, banks of streams and rivers, margins of fens, bases and ledges of bluffs, thin-soil areas of upland prairies, sand prairies, and glades; also pastures, ditches, railroads, roadsides, and open disturbed areas.

Some specimens of P. gilioides can be difficult to distinguish from P. hirsuta. Constance (1949b) suggested that, based on distribution and morphology, P. gilioides might represent a species that evolved following past hybridization between P. hirsuta and P. purshii, but had no problems distinguishing all of these taxa. G. W. Gillett (1964, 1965) came to a somewhat different conclusion. His artificial hybridization program and greenhouse studies suggested that P. purshii is often self-pollinated (other two taxa in the subgenus are mostly outcrossers), and that hybrids between it and either P. gilioides or P. hirsuta have reduced fertility. He found, however, that P. gilioides and P. hirsuta can produce relatively fertile hybrids and that some plants from central and southern Missouri were morphologically intermediate for three characters that he scored from herbarium specimens. Based on these data, he concluded that P. gilioides and P. hirsuta have formed hybrid swarms in the zone of geographic overlap of their ranges.