Calyx-tube slightly prolonged, the end filled by a cup-shaped disk, deciduous; lobes 2, reflexed. Petals 2, inversely heart-shaped. Stamens 2. Fruit indehiscent, small and bur-like, bristly with hooked hairs, 1--2-celled; cells 1-seeded.--Low and inconspicuous perennials, in cool or damp woods, with opposite thin leaves on slender petioles, and small whitish flowers in racemes, produced in summer. (Named from _Circe_, the enchantress.) 1. C. Lutetiàna, L. Taller (1--2° high); _leaves ovate_, slightly toothed; _bracts none_; hairs of the _roundish 2-celled fruit bristly_.--Very common. (Eu.) 2. C. alpìna, L. _Low_ (3--8´ high), _smooth and weak; leaves heart-shaped, thin, shining, coarsely toothed; bracts minute_; hairs of the obovate-oblong _1-celled fruit_ soft and slender.--Deep woods, N. Eng. to Ga., Ind., and Minn. (Eu.) ORDER 43. LOASÀCEÆ. (LOASA FAMILY.) _Herbs, with a rough or stinging pubescence, no stipules, the calyx-tube adherent to a 1-celled ovary with 2 or 3 parietal placentæ_;--represented here only by the genus 1. MENTZÈLIA, Plumier. Calyx-tube cylindrical or club-shaped; the limb 5-parted, persistent. Petals 5 or 10, regular, spreading, flat, convolute in the bud, deciduous. Stamens indefinite, rarely few, inserted with the petals on the throat of the calyx. Styles 3, more or less united into one; stigmas terminal, minute. Capsule at length dry and opening by valves or irregularly at the summit, few--many-seeded. Seeds flat, anatropous, with little albumen.--Stems erect. Leaves alternate, very adhesive by the barbed pubescence. Flowers terminal, solitary or cymose-clustered. (Dedicated to _C. Mentzel_, an early German botanist.) [*] _Seeds few, oblong, not winged; petals 5, not large; filaments all filiform._ 1. M. oligospérma, Nutt. Rough and adhesive (1--3° high), much branched, the brittle branches spreading; leaves ovate and oblong, cut-toothed or angled, often petioled; flowers yellow (7--10´´ broad), opening in sunshine; petals wedge-oblong, pointed; stamens 20 or more; capsule small, about 9-seeded.--Prairies and plains, Ill. to Kan. and Col., south to Tex. [*][*] _Seeds numerous, rounded and wing-margined; petals 10, large and showy; outer filaments petaloid in n. 3; capsule large, oblong; leaves sessile._ 2. M. ornàta, Torr. & Gray. Stout, 1--2° high; leaves oblong-lanceolate, deeply repand-toothed or pinnatifid, the segments acute; calyx-tube leafy-bracteate; petals 2--3´ long, yellowish-white; filaments all filiform or the outer dilated below; capsule 1{½}--2´ long; seeds narrowly margined.--On the plains, W. Dak. to central Kan. and Tex. 3. M. nùda, Torr. & Gray. More slender, 1--5° high; leaves somewhat lanceolate, rather bluntly or shortly repand-dentate; _flowers half as large as in the last; calyx not bracteate; outer filaments narrowly dilated_, sterile; _capsule about 1´ long; seeds plainly winged_.--Plains of Dak. to central Kan. and Tex. ORDER 44. PASSIFLORÀCEÆ. (PASSION-FLOWER FAMILY.)