32. Lavatera Linnaeus, Sp. Pl. 2: 690. 1753; Gen. Pl. ed. 5, 308. 1754.
Rose mallow [For Lavater family, 17th-century physicians and naturalists of Zurich] Rose mallow [For Lavater family, 17th-century physicians and naturalists of Zurich]
Steven R. Hill
Olbia Medikus; Stegia de Candolle
Herbs, subshrubs, or shrubs, perennial or annual [biennial], stellate-hairy or glabrate. Stems erect. Leaves: stipules early-deciduous, narrowly triangular, lanceolate, oblanceolate, or linear; blade lanceolate or ovate to orbiculate, narrower above, base rounded to wide-cuneate, unlobed or palmately 3–7-lobed, margins crenate or dentate or nearly entire. Inflorescences axillary solitary flowers, [fascicles], or terminal racemes; involucel present, bractlets persistent, 3, connate ca. 1/2 toward base, cupuliform. Flowers: calyx not accrescent, not inflated, lobed triangular to ovate, not ribbed; corolla broadly trumpet-shaped to nearly rotate, rose-pink, white, or purple, usually with darker purplish veins; staminal column included; ovary [9–]12–22[–40]-carpellate; ovules 1 per cell; style [9–]12–22[–40]-branched (same number as locules); stigmas introrsely decurrent, filiform. Fruits schizocarps, erect, not inflated, flattened-globose, discoid, somewhat indurate, persistent style base swollen, conic or disc-shaped; mericarps [9–]12–22[–40], drying tan or brown, 1-celled, elliptic in cross section, edges rounded, walls readily separating from seed, without dorsal spur, not beaked, sometimes slightly ridged or keeled, apex rounded, glabrous or hairy, indehiscent. Seeds 1 per mericarp, glabrous. x = 14.
Species ca. 12–25 (3 in the flora): introduced; s Europe (Mediterranean regions), sw Asia (to Kashmir), Africa (Ethiopia), Atlantic Islands (Canary Islands); introduced also widely.
Lavatera has traditionally been distinguished from Malva by its cuplike, basally fused involucellar bractlets. Based on molecular evidence, Lavatera and Malva are nearly indistinguishable, and while still accepted here based upon different criteria, Lavatera taxa eventually may be combined with Malva. Lavatera arborea Linnaeus, L. assurgentiflora Kellogg, and L. cretica Linnaeus of previous treatments have been transferred to Malva, and some epithet changes were necessary.
Lavatera cachemiriana Cambessèdes is commonly cultivated and may escape; it is similar to L. thuringiaca but has denser, long-stellate indument and the involucellar bractlets are two-thirds as long as the calyx, are broadly ovate with acute apices, fused at base into a cup about 1 cm long, barely appressed to the calyx, and are accrescent in fruit.
SELECTED REFERENCE Ray, M. F. 1995. Systematics of Lavatera and Malva (Malvaceae, Malveae)—A new perspective. Pl. Syst. Evol. 198: 29–53.