_Succulent herbs, with perfectly symmetrical flowers; viz., the petals and pistils equalling the sepals in number (3--20), and the stamens the same or double their number_,--technically different from Saxifrageæ only in this complete symmetry, and in the carpels (in most of the genera) being quite distinct from each other. Also, instead of a perigynous disk, there are usually little scales on the receptacle, one behind each carpel. Fruit dry and dehiscent; the pods (follicles) opening down the ventral suture, many-rarely few-seeded.--Stipules none. Flowers usually cymose, small. Leaves mostly sessile, in Penthorum not at all fleshy. [*] Not succulent; the carpels united, forming a 5-celled capsule. 1. Penthorum. Sepals 5. Petals none. Stamens 10. Pod 5-beaked, many-seeded. [*][*] Leaves, etc., thick and succulent. Carpels distinct. 2. Tillæa. Sepals, petals, stamens, and pistils 3 or 4. Seeds few or many. 3. Sedum. Sepals, petals, and pistils 4 or 5. Stamens 8--10. Seeds many. 1. PÉNTHORUM, Gronov. DITCH STONE-CROP. Sepals 5. Petals rare, if any. Stamens 10. Pistils 5, united below, forming a 5-angled, 5-horned, and 5-celled capsule, which opens by the falling off of the beaks, many-seeded.--Upright weed-like perennials (not fleshy like the rest of the family), with scattered leaves, and yellowish-green flowers loosely spiked along the upper side of the naked branches of the cyme. (Name from πέντε, _five_, and ὅρος, _a mark_, from the quinary order of the flower.) 1. P. sedoìdes, L. Leaves lanceolate, acute at both ends.--Open wet places, N. Brunswick to Fla., west to Minn., E. Kan., and Tex. July--Oct. Parts of the flower rarely in sixes or sevens. 2. TILLÆ̀A, Mich. Sepals, petals, stamens, and pistils 3 or 4. Pods 2--many-seeded.--Very small tufted annuals, with opposite entire leaves and axillary flowers. (Named in honor of _Michael Angelo Tilli_, an early Italian botanist.) 1. T. símplex, Nutt. Rooting at the base (1--2´ high); leaves linear-oblong; flowers solitary, nearly sessile; calyx half the length of the (greenish-white) petals and the narrow 8--10-seeded pods, the latter with a scale at the base of each.--Muddy river-banks, Mass. to Md. July--Sept. 3. SÉDUM, Tourn. STONE-CROP. ORPINE. Sepals and petals 4 or 5. Stamens 8 or 10. Follicles many-seeded; a little scale at the base of each.--Chiefly perennial, smooth, and thick-leaved herbs, with the flowers cymose or one-sided. Petals almost always narrow and acute or pointed. (Name from _sedeo_, to sit, alluding to the manner in which these plants fix themselves upon rocks and walls.) [*] _Flowers perfect and sessile, as it were spiked along one side of spreading flowering branches or of the divisions of a scorpioid cyme, the first or central flower mostly 5-merous and 10-androus, the others often 4-merous and 8-androus._ [+] _Flowers white or purple._