Sp. Pl. 2: 1024. 175.
Gen. Pl. ed. 5, 449. 1754.
Shrubs or small trees, often aromatic and resinous. Branches spreading, terete, glabrous or pubescent, often gland-dotted. Leaves persistent or deciduous; stipules absent. Leaf-blade aromatic when crushed (except M. inodora), oblanceolate, elliptic, obovate, or oblong-ovate, membranous or leathery, margins entire or serrate-denticulate, especially in distal 1/2, pubescent or glabrous, usually gland-dotted. Inflorescences ± erect, ellipsoid to short-cylindric or ovoid, appearing before or with leaves; bracts ovate, glabrous or variously pubescent. Flowers unisexual, rarely bisexual, staminate and pistillate flowers usually on different plants, infrequently on same plants. Staminate flowers: stamens (2-) 3-12 (-22), shorter or longer than subtending bract; filaments mostly distinct, often connate into branching staminal column, each branch terminated by anther; rudimentary ovary occasionally present. Pistillate flowers: ovary subtended by 2-6 broadly ovate bracteoles, these sometimes persistent and accrescent, always shorter than fruit, sometimes completely absent; styles short. Fruits globose or ovoid to lenticular, smooth or more commonly with warty protuberances, usually covered with waxy coating that dries white. x = 8.
Species ca. 50 (7 in the flora).
Myrica is often cultivated. Myrica species were used by various tribes of Native Americans for medicinal purposes. Leaves were used for a gynecological aid and an emetic; the bark, as a blood purifier and a kidney aid (D. E. Moerman 1986). Bayberry candles were used by early settlers, and they remain popular household items, both decorative and functional.
|1||Bracts of staminate flowers longer than stamens; bracteoles of pistillate flowers 2, accrescent and adnate to fruit; fruits smooth (without protuberances), lacking waxy deposit (subg. Myrica).||> 2|
|1||Bracts of staminate flowers shorter than stamens; bracteoles of pistillate flowers 4–6, not accrescent or adnate to fruit; fruits with numerous protuberances, usually covered with waxy coating that dries white or blue-white to gray (subg. Morella Loureiro).||> 3|
|2||Bracteoles of pistillate flowers glabrous; leaf margins serrate, usually minutely so, with 1–4 pairs of teeth restricted to distal 1/3 of blade; not extending s of Oregon in w part of range.||Myrica gale|
|2||Bracteoles of pistillate flowers densely pilose, especially at apex; leaf margins serrate, often coarsely so, with 4–12 pairs of teeth ± in distal 1/2 of blade; California only.||Myrica hartwegii|
|3||Staminate flowers with 6 or more stamens, rarely 2–3, especially in distal flowers; fruit wall, but not warty protuberances, pubescent.||> 4|
|3||Staminate flowers with 3–5(–7) stamens; fruit wall usually glabrous, if pubescent, warty protuberances also pubescent.||> 5|
|4||Margins of leaf blade entire, rarely serrate at apex; blade not aromatic when crushed; flowers unisexual, staminate and pistillate on different plants; restricted to Gulf Coast region.||Myrica inodora|
|4||Margins of leaf blade conspicuously serrate almost their entire length; blade fragrant when crushed; flowers bisexual, staminate, and pistillate, all on same plant; Pacific Coast region.||Myrica californica|
|5||Leaf blade densely glandular on both surfaces.||Myrica cerifera|
|5||Leaf blade densely glandular only abaxially.||> 6|
|6||Fruit wall and warty protuberances densely hirsute when young; branches whitish gray in age; leaves deciduous, membranous; fruits 3.5–5.5 mm.||Myrica pensylvanica|
|6||Fruit wall glabrous or sparsely glandular, warty protuberances ± glandular; branches black; leaves persistent or tardily deciduous, leathery; fruits 3–4.5 mm.||Myrica heterophylla|