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FNA | Family List | FNA Vol. 14 | Solanaceae

17. Lycium Linnaeus, Sp. Pl. 1: 191. 1753; Gen. Pl. ed. 5, 88. 1754.

Wolfberry, boxthorn [Greek lykion, name used by Dioscorides and Pliny for a spiny shrub, probably a species of Rhamnus supposedly from Lycia, ancient region of Asia Minor, alluding to resemblance]

Rachel A. Levin
Jill S. Miller

Shrubs, glabrous or hairy, leaves sometimes glaucous. Stems erect to prostrate, spinescent, with single (rarely) or multiple branches (often with divaricate branching). Leaves alternate, usually in fascicles (often drought-deciduous), petiolate or sessile, sometimes succulent; blade simple. Inflorescences axillary, fasciculate or solitary flowers. Flowers bisexual or unisexual, 4–5(–6)-merous, radially symmetric or calyx occasionally ± bilateral; calyx cupulate, tubular, or campanulate, sometimes accrescent in fruit; corolla white, greenish, yellowish, or lavender to deep purple lobes sometimes white with purple veins, tubular, funnelform, campanulate, or campanulate-rotate, lobes spreading or reflexed; stamens inserted at or proximal to midpoint of corolla tube, equal or unequal; anthers dorsifixed, ovate, dehiscing by longitudinal slits; ovary 2-carpellate; style filiform; stigma slightly 2-lobed. Fruits berries, juicy, occasionally hardened or drupaceous, globose to ovoid, rarely with constrictions (L. cooperi, L. macrodon, and L. puberulum). Seeds discoid to auriform, flattened. x = 12.

Species ca. 90 (18 in the flora): North America, Mexico, West Indies, South America, Eurasia, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia.

Species of Lycium typically inhabit subtropical regions, often growing in desert, coastal, or saline environments. Some species can spread vegetatively via root suckering; plants have also been known to sprout from roots. Most species of Lycium are hermaphroditic; some are gynodioecious or dioecious. At least two species, L. californicum and L. carolinianum, are polymorphic for sexual strategy, having either hermaphroditic or dimorphic (gynodioecious or functionally dioecious) populations. Most species are diploid; some are polyploid. Polyploidy is positively correlated with sexual dimorphism.

Lycium appears to have evolved in South America, with subsequent dispersal to North America and a single long-distance dispersal event to the Old World. Grabowskia Schlechtendal and Phrodus Miers were formerly treated as separate genera; they have been transferred to Lycium.

SELECTED REFERENCES Chiang Cabrera, F. 1981. A Taxonomic Study of the North American Species of Lycium (Solanaceae). Ph.D. Dissertation, University of Texas. Chiang Cabrera, F. and L. R. Landrum. 2009 Vascular plants of Arizona: Solanaceae part three: Lycium. Canotia 5: 17–26. Hitchcock, C. L. 1932. A monographic study of the genus Lycium of the western hemisphere. Ann. Missouri. Bot. Gard. 19: 179–348, 350–375. Levin, R. A. and Jill S. Miller. 2005. Relationships within tribe Lycieae (Solanaceae): Paraphyly of Lycium and multiple origins of gender dimorphism. Amer. J. Bot. 92: 2044–2053. Miller, Jill S. 2002. Phylogenetic relationships and the evolution of gender dimorphism in Lycium (Solanaceae). Syst. Bot. 27: 416–428.

1 Berries not fleshy, green to yellow, orange, or brown, seeds 2–10.   (2)
+ Berries ± fleshy, red to orange to orange-yellow; seeds 2–50+.   (5)
2 (1) Berries not constricted; flowers 4(–5)-merous; plants 0.3–0.6 m, bark pale tan to white   1 Lycium shockleyi
+ Berries constricted; flowers (4–)5-merous; plants 0.6–3 m, bark usually dark brown, sometimes reddish, purple, or black.   (3)
3 (2) Berries constricted at or distal to middle; calyx lobe lengths 0.5–1 times tube; leaf surfaces usually densely glandular-pubescent, not glaucous   2 Lycium cooperi
+ Berries constricted proximal to middle, calyx lobe lengths 1–2 times tube; leaf surfaces glabrous or pubescent, glaucous.   (4)
4 (3) Calyx lobes linear; Sonoran Desert   3 Lycium macrodon
+ Calyx lobes ovate; Chihuahuan Desert   4 Lycium puberulum
5 (1) Seeds 2, each enclosed by a hard layer forming a pyrene   5 Lycium californicum
+ Seeds 4–50+, each not enclosed by a hard layer.   (6)
6 (5) Leaves glaucous; corollas (8–)12–25 mm, funnelform   6 Lycium pallidum
+ Leaves rarely glaucous; corollas 4–16(–20) mm, tubular, funnelform, campanulate, or campanulate-rotate.   (7)
7 (6) Calyx cupulate (to tubular in L. torreyi).   (8)
+ Calyx tubular, campanulate, or tubular-campanulate.   (12)
8 (7) Corollas narrowly tubular or narrowly tubular-funnelform.   (9)
+ Corollas tubular to funnelform or campanulate-rotate.   (10)
9 (8) Corolla lobe margins glabrous or sparsely ciliate   7 Lycium andersonii
+ Corolla lobe margins densely ciliate-lanate   8 Lycium torreyi
10 (8) Corollas campanulate-rotate; coastal or wetland areas   9 Lycium carolinianum
+ Corollas tubular to funnelform; mainly desert areas.   (11)
11 (10) Leaf surfaces glabrous   10 Lycium berlandieri
+ Leaf surfaces pubescent   11 Lycium texanum
12 (7) Calyx tubular or tubular-campanulate, 2–10 mm.   (13)
+ Calyx campanulate, 2–6 mm.   (15)
13 (12) Leaf surfaces glabrous; plants with bisexual flowers only   12 Lycium ferocissimum
+ Leaf surfaces glandular-pubescent; plants with either pistillate flowers or bisexual flowers.   (14)
14 (13) Corollas deep lavender to purple, 8–20 mm; stamens included or slightly exserted; saline desert flats   13 Lycium fremontii
+ Corollas greenish white to lavender, 7–14 mm; stamens exserted 2–3+ mm from corolla in bisexual flowers; desert washes and bajadas   14 Lycium exsertum
15 (12) Leaf surfaces glabrous; pedicels 10–20 mm; corollas funnelform; occurring mainly near habitation.   (16)
+ Leaf surfaces glabrous or puberulent to densely pubescent; pedicels 1–10 mm; corollas campanulate to tubular or funnelform; not restricted to human-modified areas.   (17)
16 (15) Corolla lobes equaling or longer than tube; leaves subsessile   15 Lycium chinense
+ Corolla lobes shorter than or equaling tube; leaves petiolate   16 Lycium barbarum
17 (15) Leaf surfaces glabrous or puberulent; corollas lavender or white with purple markings, campanulate to tubular; berries 10 mm; coastal desert areas, including by the Salton Sea   17 Lycium brevipes
+ Leaf surfaces densely pubescent; corollas pale lavender to purple, narrowly campanulate to funnelform; berries 4–7 mm; inland, along desert washes and bajadas   18 Lycium parishii

  • List of lower taxa


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