Vascular Plants of Williamson County

Gilia rigidula subsp. rigidula [Polemoniaceae]
blue gilia, prickleaf gilia

Gilia rigidula Benth. subsp. rigidula, blue gilia, prickleaf gilia. Suffrutescent perennial, taprooted, rosetted or not, 1—several–stemmed at base, decumbent to spreading, mostly < 15 cm tall; shoots with pinnately lobed basal leaves and cauline leaves (sometimes appearing palmately lobed), having evenly distributed, colorless, short glandular hairs to 0.2 mm long, lacking nonglandular hairs (not cobwebby).

Stems

Stems young stems cylindric, to 1.5 mm diameter, green, woody lower stems covered with brown bark, to 4 mm diameter, internodes to 20 mm long.

Leaves

Leaves helically alternate, pinnately lobed or dissected mostly with 3, 5, or 7 units having lateral lobes subopposite, petiolate below the lowest lobes to subsessile, in range to 60 mm long, without stipules; petiole indistinct from blade axis, hemicylindric; blade axis slightly sunken along midrib, lobes ovate or obovate to elliptic or oblanceolate, the lowest pair from near the base to midblade, lobe length commonly increasing toward tip and with deep sinuses to midrib, dark green, thickish, lobes entire, acute at tip, pinnately veined, terminal lobe often having a pair of sublobes or teeth near its base.

Inflorescence

Inflorescence leafy cyme, terminal and axillary, 1—several–flowered, bracteate, having short glandular hairs on all green surfaces; bractlet subtending pedicel leaflike (flowers appearing solitary and axillary); pedicel cylindric, 10—20 mm long not increasing in fruit, flexible.

Flower

Flower bisexual, radial, 16—24 mm across; without detectable fragrance; calyx 5–lobed, 6.5—7.5 mm long increasing somewhat in fruit; tube bell–shaped, ca. 4 mm long, with 5 green ribs connected by wide translucent membranous panels, panels appressed to corolla, green ribs glandular–pubescent, membranous panels lacking hairs; lobes suberect, green axis 1–veined, with membranous margins not reaching tip; corolla 5–lobed, short trumpet–shaped, 10—14 mm long; tube barrel–shaped shallowly 5–ridged, 1.5—2 × 2.5 mm, light green, without hairs; throat indistinguishable from tube but above funnel–shaped, ca. 2 mm long, glossy green, inner surface green grading to glossy bright yellow (tinged green); lobes widely spreading, overlapping at base, ovate, 6.5—10 × 6—7 mm, dark violet–blue at base glossy bright yellow fringed white next to blue (yellow eye with yellow continuous with throat), entire, acute (obtuse) at tip, parallel–veined with 3 fine veins at base and veins not converging at tip, upper surface with minute domed cells (responsible for blue reflectance); stamens 5, fused to corolla with filaments decurrent from base, exserted; filaments alternate corolla lobes, free 1.5 mm from corolla base, suberect, subequal, 5—6 mm long, > green portion of corolla, lower filament pale green with short glandular hairs fading to white at top and without hairs above midpoint; anthers dorsifixed, dithecal, 2.5—3.6 mm long, bright yellow, longitudinally dehiscent; pollen bright yellow; nectary disc subtending ovary (not fused), somewhat funnel–shaped, ca. 0.5 × 1.3 mm, light green, nectar–producing; pistil 1, 9—10 mm long; ovary superior, ellipsoid, ± 2 × 1.5 mm, light green, not lobed, 3–chambered, each chamber with many ovules attached to center; style straight and somewhat 3–sided, pale green at base to whitish above midpoint, with some glandular hairs at function of ovary and style, lacking hairs above, 3–branched approaching tip, the branches exserted, spreading–ascending, ca. 0.7 mm long, whitish, papillate.

Fruit

Fruit capsule, loculicidal, 3–valved, to 24–seeded, subspheroid, ca. 5.5 × 4.5 mm, tannish.

Seed

Seed polygonal, 1—1.6 × 1—1.3 mm, light brown, gelatinous when wetted.

A. C. Gibson