ART. IX. _Descriptions of Three New Genera of Plants, from the State of New-York. Cylactis, Nemopanthus, and Polanisia, by_ C. S. RAFINESQUE. 1. _N. G. Cylactis._ Calyx campanulated 6 to 10 fidus, sepals a little unequal. Petals 4 to 6 equal. Many perigynous stamens. Pistils 8 to 12, ovaries sessile ovate, styles elongated, stigmas capitated. Berries few, distinct, one seeded. This new genus belongs in the analytical and natural method, (see Analysis of Nature) to the first natural class _Eltrogynia_, first natural order _Rhodanthia_, second natural family _Senticosia_, next to the genera _Rubus_, _Oligacis_, &c. It would range itself into the artificial class _Icosandria_ of the Linnæan sexual system; but not properly into any of its orders, since the number of pistils is variable, and never above 12. Only one species belongs to it, which I have discovered in company with Mr. Knevels, on the Catskill mountains. The etymology of the name derives from two Greek words meaning _radiated calyx_. It differs essentially from _Rubus_ by the unequal many cleft calyx, variable petals, and few pistils. _Cylactis montana._ Mountain cylactis--Stem herbaceous upright, unarmed, pubescent; leaves quinate, nearly smooth, upper ones sessile, stipules oblong, folioles ovate acuminate, incised, serrated, ciliated, base acute, entire, the middle one petiolated: flowers few corymbose, peduncles erect elongated bracteolated; calyx pubescent, sepals lanceolate acute, nerved, reflexed; petals cuneate-obovate, longer than the calyx. It is a small perennial plant, rising about half a foot; flowers white, blossoming in June. On the Catskill mountains near the great falls, &c. 2. _N. G. Nemopanthus._ Dioical. M. flowers calyx 5 phylle, equal, deciduous. No corolla. Stamina 5 hypogynous, alternating with the calyx. Fem. fl. calyx deciduous 5 phylle? Ovary ovate, stigma sessile 4 lobed. Berry 4 celled 4 seeded. The name means _flower with a filiform peduncle_. A shrub forms this genus, which had perhaps been united with _ilex_ by Michaux, &c.; but it differs altogether from it by the want of corolla, hypogynous stamens, sessile, style, &c. it does not even belong to the same family, but to the natural family _Rhamnidia_, natural order _Plynontia_, and natural class _Eltrogynia_, next to the genus _frangula_. In the sexual system it would belong to _Dioecia pentandria_, very far apart from _Frangula_. _Nemopanthus fascicularis._ Fascicled nemopanthus. Shrubby, leaves fasciculated, petiolate, oblong, mucronate, entire, rather undulated, membranaceous, smooth; flowers axillary fasciculated, peduncles filiform, shorter than the leaves.