562 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



Key to the genera 



1. Fruit a loculicidal capsule; carpels 3 to 5, not separating at maturity from one 



another or from the axis; flowers mostly solitary and axillary; ovules and 



seeds several in each carpel (2) . 



2. Style branches 5, elongate, finally spreading; stigmas capitate; calyx 5-lobed; 



seeds reniform; petals yellow or purple; plants suffruticose or herbaceous 



above the caudex 10. Hibiscus. 



2. Style not branched, clavate and ribbed toward the apex; calyx entire or 



shallowly dentate; seeds angulate-obovoid; petals white; plant a shrub. 



11. Gossypium. 



1. Fruit of several or many carpels, these at maturity usually separating from 



one another and from the axis, but sometimes connate and sometimes 



remaining, for a time, attached to the axis by a threadlike prolongation 



of the midrib of the carpel (3) . 



3. Style branches filiform, longitudinally and introrsely stigmatic; carpels 



reniform or subreniform, indehiscent, muticous, 1-ovulate; petals mauve 



or white; plants herbaceous (4). 



4. Stamens in one whorl at the apex of the column; involucel present, the 



bractlets narrowly linear; petals not more than 15 mm. long; plants 



annual; leaf blades crenate, often shallowly cleft, with broad, rounded 



lobes 5. Malva. 



4. Stamens more or less united into fascicles, these in 2 whorls, 1 apical and 



1 just below the apex of the column; involucel none; plants perennial; 

 leaf blades, at least the upper ones, palmately parted or divided, with 



narrow lobes 6. Sidalcea. 



3. Style branches terminating in a capitate or truncate stigma (5). 



5. Carpels sharply differentiated into a more or less reticulate indehiscent 



basal portion and a smooth dehiscent apical portion, the 2 portions 

 separated by a pronounced ventral notch, or the upper portion ex- 

 panded and winglike (6). 

 6. Apical portion of the carpel much wider than the basal portion, thin- 

 walled, winglike, muticous, the notch indistinct or none; involucel 

 none; petals yellow or pink; plants shrubby 2. Horsfordia. 



6. Apical portion of the carpel not or not much wider than the basal portion, 



not winglike, the 2 portions separated by a (usually deep) notch; 

 involucel usually present; petals bright red, orange, or mauve; plants 



herbaceous or suffruticose 3. Sphaeralcea. 



5. Carpels not sharply differentiated into a reticulate basal and a smooth 

 apical portion or, if so (in species of Sida), then the portions not 

 separated by a distinct notch and the apical portion not expanded 

 and wingUke; petals never bright red (7). 



7. Ovules, and usually the seeds, 2 or more in each carpel; carpels dehiscent 



to the base or nearly so, not reticulate (8). 

 8. Involucel none; carpels without long simple hairs, or, if these present, 

 then the petals orange yellow; column antheriferous only at and 

 near the apex 1. Abutilon. 



8. Involucel of 3 narrow bractlets; carpels hirsute with long simple 



hairs, also stellate-canescent; column antheriferous to far below 



the apex; petals pink 4. Iliamna. 



7. Ovule solitary; carpels indehiscent, or dehiscent not nearly to the 

 base (9). 



9. Involucel present; ovule ascending; carpels indehiscent. 



7. Malvastrttm. 



9. Involucel usually none or, if present, then the plant more or less 



lepidote and the petals ochroleucous; ovule pendulous or resupi- 



nate-horizontal (10). 



10. Lateral walls of the carpels persistent, firm, intact until maturity; 



carpels muticous to aristate at apex, not umbonate or spurred 



on the back, indehiscent or apically dehiscent; plants mostly 



perennial 8. Sida. 



10. Lateral walls of the carpels fragile, breaking up before maturity 

 or, if more persistent, then very thin and becoming more or 

 less lacerate; carpels muticous at apex, often umbonate, an- 

 gled, or spurred on the back; plants annual 9. Anoda. 



