Linden Family. 25 



with 15-20 anthers. Pistillate flowers with 0-10 styles. Carpels 0—10, 1- 

 seeded, beakless, minutely tipped, indehiscent, imperfectly 2-valved, separat- 

 ing 1 at maturity from the axis. 



N. dioica L. Glude M. Stem 4-0 feet high, but little branched, glabrous to 

 appressed pubescent: leaf divisions lanceolate, acuminate, incisely lobed or 

 toothed. Frequent in alluvial soil along the Upper Iowa river in Winneshiek 

 and Allamakee counties, also found in Fayette county; July. 



ABUTILON Gaertn. Ours an annual weed, with cordate leaves and 

 axillary yellow flowers. Calyx deeply 5-cleft. Petals 5, alternate. Stamens 

 many. Styles in ours about 12 or 1H; stigmas capitate. Carpels 12 or 13. 



A. avicennae Gaertn. Velnet-lcnf. Cake-print. Whole plant clothed with 

 a soft pubescence: stem 2-5 feet high; leaves long-petioled, broadly ovate, 

 taper-pointed, entire or obscurely dentate, base cordate; pedicels shorter than 

 the petioles; calyx persistent; petals yellow; carpels 2-valved. each valve 

 beaked, hairy, usually 3-seeded; flowers axillary. Waste places; June-Sep- 

 tember; common. 



SI DA L. Calyx 5-cleft. Petals 5, entire, usually oblique. Styles 5 or 

 more; stigmas capitate. Carpels as many as the styles, 1-seeded, tardily 

 separating. Seeds pendulous. 



S. spinosa L. Annual; stem 1-2 feet high, branched, minutely pubescent, 

 leaves ovate to oblong-lanceolate, serrate, with a spinous tubercle at the base 

 of the slender petiole; stipules bristle-like; peduncles axillary, shorter than 

 the petioles, 1-flowered; flowers small, yellow; carpels 5. Waste places, 

 spreading; July-September; Muscatine, Des Moines, Henry, Van Buren, 

 Decatur, Page, and Fremont counties. 



MALVASTRUM Gray. Flowers in ours solitary, in the axils of the upper 

 leaves, short-peduncled, yellow. Bractlets of the involucel 2 or 3, linear. 

 Calyx 5-cleft, the lobes ovate-triangular, pubescent. 



M. angustum Gray. Annual, somewhat hairy, 6-12 inches high; leaves 

 oblong-lanceolate or linear-oblong, remotely dentate; carpels 5, reniform, 

 at length 2-valved. Reported from Scott county. 



HIBISCUS L. Herbs, with dentate or lobed leaves and showy axillary or 

 paniculate flowers. Calyx 5-cleft, involucellate at the base by a row of linear 

 bractlets. Column long, with many lateral stamens. Styles 5, stigmas 

 capitate. Fruit a 5-eelled capsule, loculicidal. Seeds 3-many in each cell. 



H. militaris Cav. Hulberd-leaved Rose-Mallow. Perennial; stem smooth, 3- 

 4 feet high, leaves hastately 3-lobed; lobes long acuminate, serrate, middle 

 lobe much longer; flowers axillary, large, showy; calyx enlarged* in fruit; 

 corolla somewhat campanulate, purplish; capsule smooth; seeds hairy. Along 

 rivers and marshy lakes; July-August; locally frequent; Muscatine, Louisa, 

 Des Moines, Johnson, and Fremont counties. 



H. trionum L. Bladder Kctmla. Annual; stems sub-erect, hispid: leaves 

 3-parted, middle segments long, all segments sinuate-lobed or cleft; fruiting 

 calyx enlarged, membranaceous, 5-winged; flowers yellowish, with a dark 

 centre, lasting only for the day. Waste places; July-September; becoming 

 frequent. 



TILIACEAE Juss Linden Family. 

 Trees with simple alternate stipulate leaves and fibrous bark. Sepals 

 4-5 deciduous. Petals imbricated in the bud. Stameus many, polyadel- 

 phous, with 2-celled anthers. 



