1. Involucel usually absent, sometimes present in Callirhoë, Malachra, Malvella, and Sidalcea, often deciduous in Sphaeralcea; fruits schizocarps | → 2 |
1. Involucel usually present, sometimes absent; fruits schizocarps or capsules | → 23 |
2. Inflorescences subtended by boat-shaped sessile or subsessile bracts. | Malachra |
2. Inflorescences not subtended by boat-shaped sessile or subsessile bracts | → 3 |
3. Stigmas linear or filiform | → 4 |
4. Herbs, (1–)2.2(–3) m; inflorescences terminal panicles; flowers unisexual, plants dioecious; corollas white. | Napaea |
5. Anthers borne ± evenly along staminal column; staminal columns not comprised of concentric series. | Callirhoë |
5. Anthers borne distally on staminal column, staminal columns comprised of concentric inner and outer series of filaments. | Sidalcea |
6. Mericarps 1-celled; distally dehiscent, partially dehiscent, or indehiscent; seeds usually 1 per mericarp (3–6 in Abutilon; 2–6 in Herissantia) | → 11 |
7. Calyces usually shorter than fruits; seeds 1–3 per mericarp | → 9 |
8. Calyces usually 8–13 mm; mericarps with prominent, medial constriction resulting in 2 cells. | Allowissadula |
8. Calyces 4–8 mm; mericarps with obscure medial constriction (except P. umbellatum). | Pseudabutilon |
9. Styles 3–6-branched; petals 3–5 mm. | Wissadula |
9. Styles 6–12-branched; petals 6–21 mm | → 10 |
10. Mericarps with medial constriction, distal cell unwinged; seeds 1 per mericarp; Texas. | Batesimalva |
10. Mericarps without medial constriction, distal cell apically winged; seeds 2 or 3 per mericarp; Arizona, California. | Horsfordia |
11. Calyces completely enclosing fruits or leaves maplelike | → 12 |
11. Calyces closely subtending, not enclosing fruits (fruits closely invested by calyx tube in Fryxellia); leaves seldom maplelike (Anoda; Sida hermaphrodita) | → 14 |
12. Corollas white; calyces not completely enclosing fruits; leaves maplelike; east of Mississippi River. | Sida |
12. Corollas yellow or white, fading rose; calyces completely enclosing fruits; leaves not maplelike; west of Mississippi River | → 13 |
13. Corollas white, fading rose; calyces brownish-membranous at maturity; mericarps fragile-walled, unornamented. | Krapovickasia |
13. Corollas yellow; calyces green-membranous at maturity; mericarps indurate, laterally reticulate-walled, with horizontal obtuse rostrum. | Rhynchosida |
14. Fruits spheric, inflated, not indurate, setose, reflexed. | Herissantia |
14. Fruits not both spheric and inflated (can appear somewhat inflated in Fryxellia but not spheric or pendent), usually indurate, hairy, seldom setose, usually erect | → 15 |
15. Mericarps 3–6-seeded. | Abutilon |
| → 16 |
16. Leaf blades cuneate at base, otherwise broadly oblanceolate, 0.5–1.5 cm; mericarps 5; usually saline habitats. | Billieturnera |
16. Leaf blades variously shaped at base, ovate, reniform, oblong, elliptic, lanceolate, or linear, usually 1.5+ cm; mericarps 5+; seldom saline habitats (except Malvella) | → 17 |
17. Mericarps: lateral walls evanescent, spur rarely absent. | Anoda |
17. Mericarps: lateral walls persistent (firm or indurate), spur usually absent (except Fryxellia) | → 18 |
18. Plants cespitose; mericarps with dorsal spur and endoglossum. | Fryxellia |
19. Corollas yellow or yellowish, usually 6+ mm; calyces 4–10 mm, costate or not; pedicels not capillary | → 21 |
20. Mericarps 7 or 8, lateral walls prominently reticulate; leaves distichous; styles 7 or 8, purple; corollas rotate; inflorescences solitary flowers. | Meximalva |
20. Mericarps 5, lateral walls smooth or weakly reticulate; leaves not distichous; styles 5, pallid; corollas reflexed; inflorescences terminal panicles. | Sidastrum |
21. Leaf blades asymmetric; stems prostrate; indument sometimes ± lepidote; often saline habitats. | Malvella |
21. Leaf blades symmetric; stems usually erect, seldom prostrate; indument never lepidote; not saline habitats | → 22 |
22. Herbage prominently viscid; calyces divided nearly to base, not costate; fruit walls papery. | Bastardia |
22. Herbage seldom viscid; calyces usually 1/2-divided, usually costate; fruit walls indurate. | Sida |
23. Ovaries 3–5-carpellate; fruits usually capsules | → 24 |
23. Ovaries (5)6–36-carpellate; fruits schizocarps | → 34 |
24. Trees; leaves: venation pinnate; involucellar bractlets basally connate. | Lagunaria |
24. Trees, subshrubs, or herbs; leaves: venation palmate; involucellar bractlets usually distinct (except Abelmoschus, Talipariti, and Urena), not enclosing bud | → 25 |
25. Involucellar bractlets 3, distinct | → 26 |
25. Involucellar bractlets 4+, distinct or ± connate | → 27 |
26. Capsules ovoid or subglobose to oblong, dehiscent; shrubs or trees. | Gossypium |
26. Capsules oblate, indehiscent; trees. | Thespesia |
27. Calyces deciduous, spathaceous. | Abelmoschus |
27. Calyces persistent, not spathaceous | → 28 |
28. Fruits ovoid, subglobose, or spheroid, not fleshy; seeds 2–20 per locule | → 29 |
28. Fruits oblate, rarely fleshy, seeds 1 per locule | → 31 |
29. Calyces gland-dotted; ovaries 3–5-carpellate; styles usually connate to apex; stigmas 3–5, decurrent. | Cienfuegosia |
29. Calyces not gland-dotted; ovaries 5-carpellate; styles proximally connate, distally 5-fid; stigmas 5, capitate to discoid | → 30 |
30. Stipules persistent or caducous, not enlarged in bud; relatively dry habitats or freshwater swamps. | Hibiscus |
30. Stipules caducous, enlarged in bud, leaving annular scars; estuarine habitats. | Talipariti |
31. Fruits 5-angled, sections dehiscent; foliage scabrid; styles 5-fid. | Kosteletzkya |
31. Fruits not angled, indehiscent; foliage glabrous or hairy, seldom scabrid; styles 10-fid | → 32 |
32. Leaves with abaxial nectaries; involucellar bractlets 5. | Urena |
32. Leaves without nectaries; involucellar bractlets 5–9 | → 33 |
33. Petals basally auriculate, usually red; fruits fleshy, red; stamens and stigmas usually exserted. | Malvaviscus |
33. Petals usually not auriculate, lavender, pink, or yellow; fruits dry, not colored; stamens and stigmas usually included. | Pavonia |
34. Involucellar bractlets 6–12 | → 35 |
34. Involucellar bractlets (0 or)1–3 | → 36 |
35. Petals 3+ cm; mericarps 2-celled, proximal cell fertile, distal cell sterile; staminal columns 5-angled, anthers pale yellow. | Alcea |
35. Petals (0.9–)1–2 cm; mericarps 1-celled; staminal columns cylindric, anthers purple or pale pink to almost white or yellow. | Althaea |
36. Leaf blades asymmetric; herbage hairy, hairs mixed stellate and lepidote. | Malvella |
36. Leaf blades symmetric; herbage usually stellate-hairy, glabrate, or glabrous, sometimes some hairs simple, seldom lepidote | → 37 |
37. Mericarps 2-celled; seeds 2 per mericarp; corollas salmon-orange; mericarps drying black; stems prostrate to ascending. | Modiola |
37. Mericarps 1 or 2-celled, seeds 1–4 per mericarp; corollas sometimes salmon-orange; mericarps drying black, brown, or tan; stems usually erect, sometimes ascending, decumbent, or prostrate | → 38 |
38. Corollas yellow or yellow-orange, without darker veins. | Malvastrum |
38. Corollas usually white, pinkish, pink, magenta, rose-purple, rose-pink, purple, mauve, orange, red-orange, or red, sometimes salmon-orange, sometimes with darker veins | → 39 |
39. Stigmas capitate or obliquely capitate | → 40 |
39. Stigmas linear or filiform | → 43 |
40. Stigmas obliquely capitate; mericarps 8–15 mm; seeds 2–4 per mericarp. | Iliamna |
40. Stigmas capitate; mericarps to 8 mm; seeds 1–3 per mericarp | → 41 |
41. Fruits glabrous; mericarps indehiscent; seeds 1 per mericarp; herbs, annual. | Eremalche |
41. Fruits hairy; mericarps dehiscent; seeds 1–3 per mericarp; usually shrubs or subshrubs, rarely herbs | → 42 |
42. Mericarps dehiscent to base, usually smooth; seeds 1 per mericarp; involucellar bractlets persistent, 3. | Malacothamnus |
42. Mericarps proximally indehiscent, ± dehiscent apically, reticulate; seeds 1 or 2(or 3) per mericarp; involucellar bractlets persistent or deciduous, 2 or 3. | Sphaeralcea |
43. Mericarps obtusely beaked, mucronate, or cuspidate | → 44 |
43. Mericarps not beaked, mucronate, or cuspidate | → 45 |
44. Mericarps obtusely beaked or not; anthers ± evenly distributed along staminal column; staminal column single; roots usually taproots; mostly east of 103°W longitude. | Callirhoë |
44. Mericarps mucronate or cuspidate; anthers distal on staminal column; staminal column double (concentric inner and outer series of filaments); roots usually fibrous, fleshy or not; mostly west of 103°W longitude. | Sidalcea |
45. Involucellar bractlets present or absent; staminal column double (concentric inner and outer series of filaments). | Sidalcea |
45. Involucellar bractlets present; staminal column single | → 46 |
46. Mericarps elliptic in cross section, edges rounded, walls readily separating from seed; involucellar bractlets basally connate 1/2 length; style base persistent on fruit, swollen. | Lavatera |
46. Mericarps wedge-shaped in cross section, edges usually sharp, walls not readily separating from seed; involucellar bractlets usually distinct, sometimes basally connate; style bases not both persistent and swollen. | Malva |