Geranium pusillum Burm. f., little geranium. Annual, taprooted, rosetted, several—many–stemmed at base, decumbent to ascending, in range 10—25 cm tall; shoots with basal leaves and cauline leaves, cauline leaves unequal at node (1 with shorter petiole and smaller blade), stiff–hairy, with some spreading glandular hairs on vegetative plants and mostly short glandular–hairy in flowering canopy.
Stems cylindric, to 3 mm diameter, swollen just above each node, internodes to 55 mm long, green or swelling tinged pinkish, uniformly short glandular–hairy, the hairs straight and ⊥ or slightly backward–leaning and ca. 0.1 mm long, initially some to many hairs initially small glandular heads later losing heads and appearing nonglandular.
Leaves helically alternate (basal leaves) and opposite (cauline leaves), deeply palmately lobed with 5—7 principal lobes and sinuses 60—80% to base and lobes often with 3 sublobes, petiolate, with stipules; stipules 2, attached to flared base of petiole, acuminate–triangular, to 2.5 mm long, whitish and papery or with reddish midvein, conspicuously ciliate on margins; petiole cylindric except at flaring base, to 70 mm long (basal leaves) reduced upward, glandular–hairy; blade roundish, in range 11—22 mm, principal lobes wedge–shaped in outline, with oblanceolate to oblong sublobes, lobes on cauline leaves to 5 mm long, lacking red point at tip, palmately veined at base with 3 or 5 veins to principal lobes and principal veins sunken on upper surface and raised on lower surface, hirsute and short–hirsute with upward–arching hairs, hairs longer especially along veins and on margins.
Inflorescence 2–flowered cyme, arising at node on side opposite cauline leaf with another axis continuing shoot, hirsute and short–hirsute and conspicuously short glandular–hairy having colorless heads; peduncle ascending, at anthesis of first flower 3.5—4 mm long increasing 2—3× in fruit, short glandular–hairy; bractlet subtending pedicel = 2 narrowly triangular stipules, ascending, to 1 mm long, colorless, persistent; pedicel ascending to spreading, light green, densely glandular–hairy.
Flower bisexual, radial, ca. 4 mm across; sepals 5, overlapping in bud with exposed surfaces, ± erect, ovate lacking terminal awn, 2—2.3 × 0.9—1.1 mm increasing to 3 mm long and appressed, firmly attached, and erect in fruit, green with narrow membranous margins, flat (margins not inrolled), 5–veined (outer sepals) to 3–veined (inner sepals), short glandular–hairy and hirsute and short–hirsute, the longer hairs 0.5—0.8 mm especially on margins; petals 5, ascending, narrowly fan–shaped and lacking claw, in range ca. 1.8—2 × 1 mm, white at base to pink and above midpoint strong rose–purple or orchid, pinnately veined, glabrate (inconspicuous hair or hairs on white margin), notched (obcordate) at tip with shallow sinus; stamens 10 in 2 whorls, free, dimorphic, 5 fertile and 5 sterile (staminodes); filaments of fertile stamens (inner whorl) 1.5—1.7 mm long, colorless aging pinkish, flared and stiff–ciliate to midpoint, filaments of sterile stamens (outer whorl) ± 1 mm long; anthers at level of stigmas, dorsifixed, dithecal, 0.3—0.4 mm long, length < width, mostly pale purplish with purple lines where dehiscent, longitudinally dehiscent; pollen colorless; pistil 1, at anthesis 1.7—1.9 mm long; ovary superior, 5–lobed, ca. 1 × 0.6—0.7 mm, each lobe compressed side–to–side, hidden by dense cover of ascending white hairs, 5–chambered, each chamber with 1 ovule; style column evenly short glandular–hairy with radiating hairs and short–hairy, 5–branched, green to below branches, the stigmatic branches fingerlike, 0.7—0.8 mm long, light green and papillate–stigmatic on inner side, drying purplish.
Fruit schizocarp, of 5 dry, 1–seeded mericarps dehiscent on lower to inner face separating from base by coiling upward, before dehiscing with the central style segment; fruit body ellipsoid, 2 × 1 mm, dark brown, not inflated, densely short–hirsute; beak in range coiled like a comma, 5—6 mm long, attached at upper point on inner face of fruit body, with glandular hairs on inside of coil.
Seed ovoid compressed, 1.3 × 0.9 × 0.4—0.5 mm, dull red, often sunken on 1 or 2 faces, lacking pits (smooth), with oblique hilum at base, tardily dehiscent from mericarp.
A. C. Gibson