LOASACE.E. (LOASA FAMILY.) 135 



* * * Stamens 4 : petals rather persistent : carpels even on the back : leaves chiefly 

 scattered, or wanting on the flowering stems. 



5. M. m II bi if II mil, Nutt. Immersed leaves pinnately parted into about 

 10 very delicate capillary divisions; the emerging ones pectinate, or the upper floral 

 linear and sparingly toothed or entire ; flowers mostly perfect; fruit (minute) 

 smooth. Van 1. NA.TANS : stems floating, prolonged. Var. 2. CAPILLA 

 CEDM : stems floating, long and very slender ; leaves all immersed and capil- 

 lary. Var. 3. Liii6suM : small, rooting in the mud; leaves all linear, incised, 

 toothed, or entire. Ponds and ditches, Massachusetts to New Jersey, Penn., 

 and southward, near the coast. July - Sept. 



6. M. teiicll 11111, Bigelow. Flowering stems nearly leafless and scape-like, 

 (3' -10' high), erect, simple ; the sterile shoots creeping and tufted; bracts 

 small, entire ; flowers alternate, moncecious ; fruit smooth. Borders of ponds, N. 

 New York, New England, and northward. July. 



9. H1PPURIS, L. MARE'S TAIL. 



Calyx entire. Petals none. Stamen 1, inserted on the edge of the calyx. 

 Style single, thread-shaped, stigmatic down one side, received in the groove be- 

 tween the lobes of the large anther. Fruit nut-like, 1-celled, 1 -seeded. Peren- 

 nial aquatics, with simple entire leaves in whorls, and minute flowers sessile in 

 the axils, perfect or polygamous. (Name from limos, a horse, and otpd, a tail.) 



\ II. Vlllgaris, L. Leaves in whorls of 8 or 12, linear, acute. Ponds 

 and springs, New York to Kentucky and northward : rare. Stems simple, 1- 

 2 high. Flowers very inconspicuous. (Eu.) 



ORDER 44. LOASACE^E. (LOASA FAMILY.) 



Herbs, with a rough or stinging pubescence, no stipules, Hie calyx-tube ad~ 

 hereni to a 1-celled ovary icith 2 or 3 parietal placentce: represented only 

 by the genus 



1. 1IENTZEL,IA, Plum. (BART6xiA, Nutt.) 



Calyx -tube cylindrical or club-shaped ; the limb 5-parted, persistent. Petals 

 5 or 10, regular, spreading, flat, convolute in the bud, deciduous. Stamens in- 

 definite, rarely few, inserted with the petals on the throat of the calyx. Styles 

 3, more or less united into one : stigmas terminal, minute. Pod at length dry 

 and opening irregularly, few - many-seeded. Seeds flat, anatropous, with little 

 albumen. Stems erect. Leaves alternate. Flowers terminal, solitary or 

 c\mose-clustered. (Dedicated to C. llentzd, an early German botanist.) 



1 ITI. oligosperma, Nutt. Rough and adhesive (1- 3 high), much 

 branched, the brittle branches spreading ; leaves ovate and oblong, cut-toothed 

 or angled ; flowers yellow (7''- 10" broad), opening in sunshine ; petals wedge- 

 oblong, pointed ; stamens 20 or more : filaments filiform : pod small, about 9- 

 seeded. 1J. Prairies and plains, Illinois and southwestward. 



