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Key to Phacelia

Hydrophyllaceae

Phacelia

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1 Robust, viscid, and strongly-scented annuals or biennials; [OK and TX]; (subgenus Crenulatae).
  2 Corolla broader, campanulate, blue, purplish, or white; basal leaves ovate, 1- or 2-pinnate or pinnatifid
  2 Corolla narrow, salverform, pink or pale lavender; basal leaves broadly ovate to orbicular, crenate to shallowly lobed
1 Delicate, mostly nonglandular, and unscented or lightly-scented annuals; [more widespread]; (subgenus Cosmanthus).
    3 Corolla lobes fimbriate; ovules 2 to each of the 2 placentae (or 4 in P. gilioides); seeds 4 (or 6-8 in P. gilioides) per capsule.
      4 Corolla lobes conspicuously pilose on the back; ovules 4 per placenta (carpel); seeds (6-) 8 per capsule
        5 Corolla white (rarely slightly lavender); pubescence of the stem spreading; lobes of cauline leaves mostly obtuse; seeds 3.0-3.5 mm long
        5 Corolla lavender to blue; pubescence of the stem appressed; lobes of cauline leaves mostly acute; seeds 1.5-3.0 mm long
          6 Ovary below the apex pubescent; outer (lower) surface of corolla lobes usually pubescent; pedicels often short (< 12 mm long)
          6 Ovary below the apex glabrous; outer (lower) surface of the corolla lobes glabrous (or rarely with a very few hairs); pedicels usually > 8 mm long
             7 Stamens 1.5-2 mm long; style 1.5-2 mm long; corolla tubular; seeds globose-ovoid, nearly spherical, 4 per capsule.
               8 Pubescence of the middle stem (from 2nd to 5th node from the base) consisting of appressed to ascending, stiff, pointed hairs, sometimes also with a few gland-tipped hairs < 2 mm long; terminal leaflet of leaves directly subtending an inflorescence with acute to cuneate base; flowers medium blue; [of rivers in the Atlantic drainage, also west of the Appalachians in rivers of the Mississippi drainage]
               8 Pubescence of the middle stem spreading or even retrorse, most of the hairs weak and twisted, and many of them glandular-tipped and > 2 mm long; terminal leaflet of leaves directly subtending an inflorescence with obtuse to rounded or truncate base; flowers light blue; [of rivers in the Mississippi drainage]
             7 Stamens 3-10 mm long; style 3-15 mm long; corolla rotate to broadly campanulate; seeds ovoid-angled, 4-20 per capsule.
                 9 Corollas 8-20 mm across; plants 10-60 cm tall; ultimate segments of the leaf 15-45 mm long, 10-30 mm wide.
                   10 Seeds 2.5-4 mm long, black; pedicels recurved in fruit; branches of the inflorescence glandular-pubescent; [east of the Mississippi River, and also n. AR and s. MO]
                     11 Basal leaves pinnate-pinnatifid, with 5 main segments, these segments pinnately divided; stamens 12-16 mm long; corolla pale blue
                     11 Basal leaves pinnate, with 3-5 main segments, these segments coarsely toothed; stamens 5-13 mm long; corolla purple
                   10 Seeds 1.5-2.2 mm long, brown or black (only P. strictiflora), fruiting pedicels erect, spreading, weakly ascending, or reflexed; branches of the inflorescence variously pubescent but not glandular (short glands mixed with eglandular pubescence on peduncles of P. patuliflora var. patuliflora); [mostly west of the Mississippi River and rare in AL and MS].
                       12 Basal leaves scarcely rosulate, pinnate or pinnatifid; fruiting pedicels spreading, ascending, or reflexed, slender and usually longer than fruiting calyces.
                            14 Peduncles with short glandular pubescence dispersed among an even vestiture of canescent or villous hairs and scattered hirsute pubescence; calyx lobes oblong to narrowly lanceolate with obtuse apices and evenly hirsute margins; [sandy or granitic soils in se. to c. TX]
                       12 Basal leaves forming a conspicuous rosette, shallowly toothed or lobed; fruiting pedicels strictly erect, shorter to slightly longer than the fruiting calyces.
                              15 Basal leaves bright green, slightly succulent, glabrate beneath, persistently rosulate, and shallowly toothed; cauline leaves broad and shallowly toothed; calyces of lower flowers disproportionately enlarging in fruit; [OK and nc. TX]
                              15 Basal leaves dull and grayish, thin, pubescent beneath, basal leaves withering, and lobed or divided; cauline leaves narrower and lobed to pinnatifid; calyces of all flowers relatively equal.
                                  17 Branches slender, to 1.5 mm thick; cauline leaves remote, oblong-ovate, subpinnatifid, lobes usually obtuse; [OK south and east to ne. TX and nw. LA; disjunct to AL and MS]
                 9 Corollas 5-13 mm across; plants 5-40 cm tall; ultimate segments of the leaf 5-15 mm long, 5-9 mm wide.
                                             22 Upper rosette/lowest cauline leaves more pinnately dissected with 4-8 distinct leaflets and a total of an additional 2-4 lobes on those leaflets, and a narrow terminal leaflet 4-8 mm × 3-4 mm; cauline leaves (third below inflorescence) with 2-6 leaflets and those usually with some additional lobes; corolla small, lobes < 4.3 mm × < 3.5 mm; granite outcrops and peripheral regions, abundant on some roadsides and lawns; [Piedmont of AL and GA north to McCormick Co., SC]
                                             22 Upper rosette/lowest cauline leaves usually less dissected (< 6 leaflets) and rarely with additional lobing, and a wider terminal leaflet 4-10 mm × 3-7 mm; cauline leaves (third below inflorescence) with 1-4 leaflets, rarely with additional lobes; corolla larger, lobes usually > 4 mm × > 3 mm.
                                               23 Corolla more dish-shaped; that is, shallowly concave (best viewed on live specimens), lobes > 4.5 mm wide; upper rosette/lowest cauline leaves usually with < 4 leaflets + lobes, terminal leaflet wider than other leaflets; [calcareous glades and surrounding areas of the Nashville Basin]
                                               23 Corolla bowl-shaped or more deeply concave, lobes usually < 5.5 mm wide; upper rosette/lowest cauline leaves usually with > 4 leaflets + lobes; terminal leaflet equal to or wider than other leaflets; [east of the Cumberland Plateau].
                                                 24 Upper rosette/lowest cauline leaves usually with 2–6 leaflets sometimes with a few additional lobes, terminal leaflet smaller (approximately 5.5 mm × 4.0 mm); terminal leaflet of cauline leaf (third below inflorescence) usually smaller (approximately 5.0 mm × 2.5 mm); corolla lobes 3.5–5.2 mm × 3.0–4.8 mm; granite outcrops and peripheral areas including roadsides; [Piedmont of SC (and adjacent NC?) and Allendale and Bamberg counties, SC]
                                                 24 Upper rosette/lowest cauline leaves usually with 0–4 leaflets, very rarely with additional lobes, terminal leaflet larger (approximately 7.0 mm × 5.0 mm); terminal leaflet of cauline leaf (third below inflorescence) usually larger (approximately 7.0 mm × 3.5 mm); corolla lobes > 4.5 mm long and > 4.0 mm wide; rocky woods, floodplain forests, shale barrens, and ruderal areas including roadsides and railroad embankments; [Mountains, Piedmont, Coastal Plain; PA and south, in the uplands to n. GA, and Coastal Plain to Charleston Co., SC].
                                                    25 Sepals (in flower) 2.0-3.0 mm long; petals 3.5-5 mm long; marginal bristles of sepals 0.4-0.7 mm long; basal leaves with 4-5 pairs of lateral leaflets, the terminal leaflet about the same size and unlobed; cauline leaves with 2-4 pairs of narrow lobes; [of granitic flatrocks and domes of the Piedmont of SC and southwestward]
                                                    25 Sepals (in flower) 2.6-4.0 mm long; petals 4-6 mm long; marginal bristles of sepals 0.6-0.9 mm long; basal leaves with 1-3 pairs of lateral leaflets, the terminal leaflet larger and usually 3-lobed; cauline leaves with 1-3 pairs of rather broad lobes; [of various habitats, including granitic flatrocks and domes]