Lyonia

  • Authority

    Luteyn, James L., et al. 1995. Ericaceae, Part II. The Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae, and Vaccinioideae P.P.). Fl. Neotrop. Monogr. 66: 560. (Published by NYBG Press)

  • Family

    Ericaceae

  • Scientific Name

    Lyonia Nutt.

  • Type

    Type species. Desmothamnus lucidus (Lamarck) Small [ = Lyonia lucida (Lamarck) K. Koch]. Arsenococcus Small in Small & Carter, Fl. Lancaster Co., 218. 1913. Type species. Arsenococcus ligustrinus (Linnaeus) Small ( = Lyonia ligustrina (Linnaeus) de Candolle).

  • Synonyms

    Cynanchum, Xolisma, Lyonia ferruginea (Walter) Nutt., Neopieris, Neopieris mariana Britton, Lyonia mariana (L.) D.Don, Desmothamnus, Desmothamnus lucidus (Lam.) Small, Arsenococcus, Arsenococcus ligustrinus (L.) Small

  • Description

    Genus Description - Evergreen [or deciduous] shrubs or trees to 18 m, often from an underground, woody, globose to elongated burl, or occasionally forming thickets by means of horizontal underground rhizomes, with terete or angled branches and gray to reddish brown, longitudinally furrowed bark; indumentum of unicellular hairs and multicellular, biseriate-stalked, ferruginous, peltate scales or swollen-headed hairs; buds usually with 2 outer, imbricate scales, glabrous to densely pubescent. Leaves chartaceous to coriaceous, often reddish on young shoots, densely to sparsely covered with peltate scales or swollenheaded hairs on both surfaces, often with unicellular hairs on major veins or densely covering abaxial surface, [occasionally papillose or glaucous below]; margin entire to irregularly and obscurely toothed, strongly toothed, [or serrulate]; venation brochidodromous [to eucamptodromous] with midvein prominent and 3° veins reticulate to percurrent; petiole vascular bundle usually bifacial. Inflorescences axillary, [racemose,] fasciculate, [or paniculate]; floral bracts solitary, small to large; pedicels with 2 often caducous, lateral bracteoles at or near base. Flowers perfect, 4-7(-8)-merous, usually fragrant; calyx valvate to imbricate, usually articulate with pedicel, usually persistent in fruit; corolla cylindrical to urceolate (campanulate or cylindrical with swollen base), white to red, with short, imbricate lobes, very sparsely to densely covered with peltate scales or swollen-headed hairs (with a few unicellular hairs) on abaxial surface, glabrous on adaxial surface; stamens 8-14(-16) in 2 whorls, included, the filaments flattened, slightly to strongly expanded near base, geniculate, whitish, roughened, [papillose or with long, unicellular hairs,] with or without a pair of short, spurlike appendages below anther-filament junction, the anthers ovoid, brown, minutely papillose, lacking apical awns, dehiscing by large, introrse-terminal, elliptic pores, always with white line of disintegration tissue on back of each lobe extending at least along apex of filament and along upper edge of spurs, when present; pollen in tetrads, without viscin strands; ovary 4-7(-8)-locular, glabrous to densely covered with unicellular hairs, peltate scales, or swollen-headed hairs, with placentae axile, positioned subapically to nearly basally on columella, slightly bilobed, nectariferous disc an enlargement of base of ovary wall, variously developed and lobed; style columnar, usually at least slightly swollen near base, straight, impressed into apex of ovary, included to slightly exserted; stigma truncate to capitate. Capsules erect, with pale, thickened sutures usually separating from valves in dehiscence; placentae persistent on columella. Seeds very small, brown, oblong-ovoid to linear or spindleshaped, the ends sometimes truncated or with sterile extensions or "tails," the testa loose, thin, composed of single layer of very much elongated, thin-walled cells. 2n = 24.

  • Discussion

    Measurements and Terminology; Axillary buds are covered by two scales unless otherwise indicated. All measurements (except plant height, which was recorded in the field or taken from information included on specimen labels, and leaf thickness, which was measured on thin sections of leaves previously softened in water) included in the descriptions of species have been taken directly from dried herbarium material. The width of the calyx lobes was measured midway between the apex and the point where they join with the adjacent lobes; the width of all other structures was measured at the widest point. All drawings of flowers, stamens, anthers, and petiole and lamina anatomy were made either from material preserved in FAA or from herbarium material previously expanded and softened by boiling in water with a detergent solution. Drawings of capsules, seeds, leaves, and buds were made from dried material. As used here, "glabrous" and "pubescent" refer to the presence or absence of unicellular hairs; the presence, distribution, and density of multicellular hairs is described separately. The indumentum of the buds is only mentioned if it differs from that of the stems.

  • Distribution

    A genus of 36 species (52 taxa) occurring in E Asia (Japan to Pakistan, south to Malay Peninsula), Greater Antilles (including St. Thomas), and North America (E United States and Mexico).

    Japan Asia| China Asia| Bhutan Asia| Nepal Asia| India Asia| Pakistan Asia| Malaysia Asia| Myanmar Asia| Thailand Asia| Cuba South America| Haiti South America| Dominican Republic South America| Puerto Rico South America| Jamaica South America| Cayman Islands South America| United States Virgin Islands South America| United States of America North America| Mexico North America|