house-leek, in botany: A genus of plants belonging to the order of dodecagynia, and to the clas of dodecandra; and in the natural method ranking, under the 13th order, Succulent. The calyx is divided into 12 parts; the petals are 12, and the capsules... containing many seeds. There are 12 species; the arboreum, canariense, glutinosum, glandulosum, tectorum, globiflorum, villosum, tortuosum, arachnoideum, montanum, fedetorum, and menanthea. Linnaeus has only eight of these. The tectorum alone is a native of Britain. The stalk is about a foot high; the radical leaves are thick, oval, pointed, fringed, and spreading in a rosette; those on the stem are imbricated and membranous; the flowers are pale red and sessile, and grow on curved terminal bunches. It is frequent on the tops of housetops, and flowers in July.

The following chemical description of this species is given by Lewis: "The leaves of house-leek, of no remarkable smell, discover to the taste a mild subacid austerity; their expressed juice, of a pale yellowish hue when filtered, yields on infusion a deep yellow, tenacious, mucilaginous mass, considerably acidulous and acerb; from whence it may be presumed, that this herb has some claim to the refrigerant and refringent virtues that have been ascribed to it. It is observable that the filtered juice, on the addition of an equal quantity of rectified spirit of wine, forms a light white coagulum, like cream of fine pomatum, of a weak but penetrating taste: this, freed from the fluid part, and exposed to the air, almost totally exhales. From this experiment it is concluded by some, that house-leek contains a volatile alkaline salt; but the juice coagulates in the same manner with volatile alkaids themselves, as also with fixed alkaids: Acids produce no coagulation."