394 AMAKANTHACEAE 



the branches : utricles indehiscent, slightly over 1 mm. long : seed lenticular, less than 1 

 mm. long, shining. 



On river banks, or in moist soil, Manitoba to Wisconsin, Tenne.ssee and Nebraslca. Summer and 

 fall. 



4. AC ANTHO CHITON Torr. 



Annual herbs, with smooth and glabrous foliage. Leaves alternate : blades elongated, 

 entire, acuminate, spine-tipped, slender-petioled. Flowers dioecious, in axillary clusters. 

 Staminate flowers bractless, with 5 acuminate sepals and -5 stamens. Filaments distinct. 

 Anthers 2-celled. Pistillate flowers furnished with large rigid-tipped bracts. Perianth 

 wanting. Ovary 1-celled. Styles 2-4. Ovule solitary, erect. Utricle flattened, mem- 

 branous, circumscissile. 



1. Acanthochiton Wrightii Torr. Foliage glabrous. Stems erect, 2-5 dm. tall, 

 sparingly or rather freely branched, ridged : leaf-blades linear or nearly so, 2-8 cm. long, 

 minutely awn-tipped, prominently nerved beneath, erose or undulate, slender-petioled : 

 bracts various, those of the staminate inflorescence inconspicuous, those of pistillate plants 

 conspicuous, more or less interlocking, broadly cordate, 6-7 mm. long, awn-tipped, scarious- 

 margined and with reticulated faces. 



In and near the valley of the Rio Grande, Texas and New Mexico, and adjacent Mexico. Spring 

 to fall. 



5. ACHYRANTHES L. 



Herbs or sometimes shrubby plants, with often conspicuously slender and elongated 

 branches. Leaves opposite : blades sim2:)le, entire, petioled or sessile. Flowers perfect, 

 in slender elongated often interrupted spikes, commonly deflexed. Calyx firm, often be- 

 coming very hard : sepals 4-5, narrow, nearly equal, acuminate or awn-tipped. Stamens 

 5, or rarely fewer : filaments filiform-subulate : anthers 2-celled. Ovary 1-celIed, some- 

 what flattened : style filiform : stigma capitate. Ovule solitary. Utricle included, mem- 

 branous, indehiscent. 



1. Achyranthes obtusifolia Lam. Plant 4-12 dm. tall. Stems more or less ex- 

 tensively branched, finely pubescent, ridged : leaves mainly opposite, with clusters of 

 smaller leaves or short branches in the axils ; blades rhombic-ovate to obovate or cuneate, 

 1-3 cm. long, truncate or refuse at the apex, each Avitli an abrupt tip, prominently nerved 

 beneath, short-petioled : spikes virgate, 2-6 dm. long, mostly simple, somewhat interrupted 

 below, finely hirsute : flowers deflexed, barely 4 mm. long : sepals acute, glabrous or nearly 

 so, rigid, surpassing the awn of the firm bract : utricle included, with a sharp rim at the top. 



In sand. Key West and tropical America. Spring to fall. 



6. BRAYULINEA Small. 



Perennial pubescent herbs, with prostrate or decumbent stems. Leaves opposite : 

 blades rather broad, entire. Flowers perfect, subtended by bracts, in axillary clusters. 

 Sepals 5, pubescent. Stamens 5, perigynous : filaments broad and sometimes slightly 

 united at the base, inserted at the base of the sepals : anthers 1-celled. Ovary 1-celled, 

 flattened : style short : stigma notched. Ovule solitary. Utricle membranous, indehis- 

 cent. Seed smooth. [(rUi'Wemiwea H.B.K., not Neck.] 



1. Brayulinea densa fWilld. ) Small. Foliage lanuginose. Stems branched at the 

 base, the branches spreading or prostrate, forking, , often zigzag : leaf-blades spatulate, 

 elliptic or oblong-spatulate, or oval-elliptic, 7-15 mm. long, acute, glabrous or nearly so 

 above, punctate, short-petioled, or sessile above : flowers minute, in clusters 5-10 mm. in 

 diameter : bracts nearly equal, silvery white, ovate and acute to oblong-ovate and obtuse, 

 glabrous or nearly so : sepals about 1.5 mm. long, ol)long to ovate, acute, woolly at tlie 

 base: utricle included. lOuiUemi7iea densa (WiUd.) Moq.] 



On plains, Texas to New Mexico, south to Mexico and tropical America. Spring to fall. 



7. GOSSYPIANTHUS Hook. 



Perennial hei'bs, with woolly foliage and branching prostrate stems. Leaves mainly 

 basal : blades entire, without rigid tips. Flowers perfect, subtended by hyaline bracts, in 



