1. Nutlet margins rounded (rarely +/- acute-angled in J. angustifolia, but not sharply angled, lineate-rimmed, or narrowly winged)
2. Flowers bracteate
3. Calyces 2--3 mm, hairs ascending hirsute, <1 mm; plants flowering in summer ...... J. albida
3' Calyces 3--4 mm, hairs spreading hispid, 1--1.5 mm; plants flowering in spring ...... J. mexicana
2' Flowers ebracteate ...... J. angustifolia
1' Nutlet margins sharply angled, either lineate-rimmed or narrowly winged
4. Nutlets heteromorphic in size and/or sculpturing (rarely homomorphic in J. angelica), largest more firmly attached than consimilar three
5. Plants herbaceous throughout or occasionally woody at base; pedicels 0--1.5 mm in fruit, ascending
6. Stem hairs strigose and hispid; pedicels 0.5--1.5 mm in fruit; calyx in fruit 2.5--4 mm long; corolla limb 2.5--4 mm wide;
largest/odd nutlet 1.4–1.7 mm long ...... J. inaequata
6' Stem hairs strigose only; pedicels 0--0.5 mm in fruit; calyx in fruit 2--2.1(2.5) long; corolla limb 0.5--1 mm wide;
largest/odd nutlet 0.9--1.2 mm long ...... J. angelica
5. Plants woody at base, often resembling a subshrub; pedicels 1--4(--6) mm in fruit, spreading ...... J. racemosa
4. Nutlets homomorphic (rarely slightly heteromorphic in J. costata), nutlets similar in strength of attachment.
7. Stems with prominent, often woody central axis; lower leaves often elliptic with narrowly attenuate base resembling petiole;
pedicels 1--1.5 mm in fruit; nutlets (1.5--)1.8--2.5 mm, margins flat-winged, wing ≥0.2 mm ...... J. holoptera
7' Stems branched throughout or basally; lower leaves linear to lanceolate, base not strongly attenuate, not resembling petiole;
pedicels 0--0.5 mm in fruit; nutlets 0.8--1.8(--2) mm, margins sharp-angled, lineate-rimmed, or adaxially narrowly bent-winged,
if so, wing ≤0.1 mm
8. Calyx ovoid, 2--2.5 mm in fruit, deciduous; bracts oblong to oblanceolate; nutlets 0.8--1.2 mm, margin lineate-rimmed,
adaxial surface strongly incurved-arched; stems branched basally ...... J. pusilla
8' Calyx ovate-oblong, 4--6 mm in fruit, persistent; bracts lanceolate, long-acuminate; nutlets 1.2--1.8(--2) mm, margin narrowly
winged, adaxial surface flat to slightly concave; stems branched throughout ...... J. costata