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     The pollination biology of the genus is poorly known.  Judd (1981), however, observed Bombus sp. and Campsomeris sp. visiting the flowers of L. ferruginea and L. fruticosa, two species of the southeastern U.S. Floral visitors of the West Indian species have not been observed, but because their floral morphology is similar to that of L. ferruginea, they may also be pollinated by various hymenoptera (see Judd, 1981).
     Many species of Lyonia are useful in erosion control on steep hillsides, and are used for fuel by the local inhabitants.  All species readily sprout from the base after cutting and thus provide a constant source of firewood if not overused.  Several species have been used as ornamental shrubs, but none has become very popular (Judd, 1981).
     From a conservation point of view, Lyonia rubiginosa was one of the earliest West Indian lyonias to be described, but this species has not been collected since 1887.  It is possible that this species is extinct.  Several other species have the potential to become endangered because they have limited geographical ranges in which habitat destruction is occurring rapidly, e.g., L. alpina, L. ekmanii, L. elliptica, and L. longipes.

LYONIA Nuttall, Gen. N. Am. Pl. 1: 266. 1818, nom. cons., non Lyonia Elliott, Sketch bot. S. Carolina 1: 316.  1817 (=Cynanchum Linnaeus, Asclepiadaceae), nec Lyonia Rafinesque, Med. Repos. New York, ser. 2, 5: 353.  1803 (=Polygonella Michaux, Polygonaceae). Xolisma Rafinesque, Am. Mon. Mag. Crit. Rev. 4: 193. 1819; Small, N. Amer. Fl. 29: 33-102. 1914; Judd, J. Arnold Arbor. 62: 63-209, 315-436. 1981; Berazaín, Feddes Repert. 96: 631-649. 1985;  Liogier, La Flora de la Española. Vol. 5. Univ. Central del Este, Vol. 69. Serie Cien. 26. 1989; Berazaín, Ericaceae, Flora de la República de Cuba. Fontqueria 35: 21-80. 1992;  Judd, Fl. Neotrop. Monogr. 66: 222-294.  1995.  Lectotype species.  Lyonia ferruginea (Walter) Nuttall; see I.C.B.N. 261.  1956, and Rickett & Stafleu, Taxon 9: 75. 1960.
 

Neopieris Britton in Britton & Brown, Illus. Fl. Ed. 2. 2: 690. 1913.  Type species.  Neopieris mariana (Linnaeus) Britton [=Lyonia mariana (Linnaeus) D. Don].

Desmothamnus Small, Shrubs Florida, 96. 1913.  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) A.P. de Candolle].

     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 swollen-headed 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 3o 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- to 7-(or 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;  filaments flattened, slightly to strongly expanded near base, geniculate, whitish, roughened, [papillose or with long, unicellular hairs,] with or without a pair of short, spur-like appendages below anther-filament junction; 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- to 7-(or 8-)-locular, glabrous to densely covered with unicellular hairs, peltate scales, or swollen-headed hairs, with placentae axile, positioned subapically to nearly asally 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 spindle-shaped,  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.  Chromosome number: 2n=24.

Key to Neotropical Species                                                                                               Back to Top

     [Notes on measurements and terminology used in the key:  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.
     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.]

1.  Abaxial surface of leaves, pedicels, and calyx with minute, gland-headed hairs;
     leaves with an intramarginal vein (sect. Maria) ......................................  L. lucida.
1.  Abaxial surface of leaves, pedicels, and calyx lepidote; leaves lacking an
     intramarginal vein (sect. Lyonia).
     2.  Lamina with a dense covering of unicellular hairs on abaxial surface, or at
          least with a few such hairs on margin of some leaves.
          3.  Leaves with veins prominently and coarsely raised-reticulate (raised ca.
               0.2-0.4 mm) on abaxial surface, the petiole and midvein of adaxial
               surface lacking unicellular hairs; corollas 7-13 mm wide;  capsules 5.5-
               10.5 mm wide, 6- or 7-valved.
               4.  Leaves to ca. 13 cm long, cuneate to rounded at base, quaternary and
                    higher order veins slightly depressed on adaxial surface; corollas
                    broadly urceolate to campanulate; ± erect shrub to ca. 6 m trees ...
                    .............................................................................................. L. buchii.
               4.  Leaves usually not over ca. 6 cm long, cordate at base (to cuneate
                    in immature plants), quinary and higher order veins ± obscure on
                    adaxial surface; corollas urceolate; widely branched shrub, usually
                    not over ca. 2 m .............................................................  L. heptamera.
          3.  Leaves with veins obscure to finely raised-reticulate (raised up to ca.
               0.15 mm) on abaxial surface, the petiole and at least extreme basal
               portion of midvein of adaxial surface with unicellular hairs; corollas
               1-6.5 mm wide; capsules 1-6 mm wide, mainly 4- and/or 5-valved.
               5.  Calyx lobes ± densely lepidote on both surfaces, 3.5-6 mm long;
                    corollas always densely lepidote, scales usually yellowish-gold ..........
                    ...........................................................................................  L. latifolia.
               5.  Calyx lobes abaxially sparsely to densely lepidote, adaxially at most
                    with few scales near margins, 0.5-3(-4) mm long; corollas sparsely to
                    densely lepidote, the scales rusty to reddish, brownish, or orangish,
                    but not strikingly yellowish-gold.
                    6.  Articulation between pedicel and capsule not developed, pedicel
                         appearing swollen just below capsule; capsules small, very narrowly
                         ovoid, only 1-2 mm wide, always 4-valved;  leaves entire; corollas
                         2-3 mm long; calyx  lobes 0.5-1 mm long .................... L. glandulosa.
                    6.  Articulation between pedicel and capsule ± prominent, or at least
                         visible as slight constriction; capsules narrowly to widely ovoid or
                         ellipsoid to subglobose, 1.5-7 mm wide, 5- and/or 4-valved;
                         leaves entire or obscurely to irregularly toothed; corollas 3-8 mm
                         long; calyx lobes 0.7-3(-4) mm long.
                         7.  Leaves with veins of abaxial surface moderately to strongly,
                              and finely raised-reticulate (secondary through quinary veins
                              raised, although often not visible without magnification), the
                              adaxial surface sometimes rough; capsules ± narrowly ovoid
                              (to sometimes ovoid in L. urbaniana), 1.5-3.5 mm wide.
                              8.  Leaves widely ovate to widely elliptic, length/width quotient
                                   mostly less than 1.6; scales of new growth orangish to
                                   orange-brown; corollas 2-4 mm long;  capsules on
                                   individual plant 4-(or 4- and 5-)-valved, 1.5-2(-2.5) mm
                                   wide ................................................................ L. microcarpa.
                              8.  Leaves ovate to elliptic, length/width quotient mostly greater
                                   than 1.6;  scales of new growth tan to ± dark brown;
                                   corollas 3-5.5 mm long; capsules on individual plant 5-
                                   and/or 4-valved, (1.5-)2-3.5 mm wide.
                                   9.  Leaves usually to 3 or 4 cm long, adaxial surface smooth,
                                        abaxial surface usually not densely dark brown lepidote;
                                        capsules nearly always 5-valved, elongated-ovoid, usually
                                        with slightly constricted apex, the valves slightly S-shaped.
                                        .......................................................................... L. tinensis.
                                   9.  Leaves not over ca. 3.5 cm long, adaxial surface
                                        roughened, abaxial surface often densely brownish
                                        lepidote; capsules 5- and/or 4-valved, ± ovoid, the
                                        apex not constricted, the valves straight-sided or convex
                                        ....................................................................... L. urbaniana.
                         7.  Leaves with veins of abaxial surface obscure, or if visible, then
                              only slightly or laxly reticulate (higher order veins not raised),
                              the adaxial surface never rough; capsules ovoid or ellipsoid to
                              subglobose, (2-)2.5-7 mm wide.
                              10.  Flowers 4-merous; capsules long-ovoid, 2-3 times as long
                                     as wide, 2-3(-3.5) mm wide ................................ L. elliptica.
                              10.  Flowers mainly 5-merous (but often 4-merous in L. alpina,
                                     which has leaves 1-3 by 1-2 cm vs. 3-7.3 by 1.2-5.2 cm
                                     in L. elliptica); capsules ovoid or ellipsoid to subglobose,
                                     1-2 times as long as wide, 2.5-7 mm wide.
                                     11.  Corollas ± densely lepidote, long-urceolate; capsules
                                            4-7 mm wide;  calyx lobes 1.2-3(-4) mm long;
                                            leaves entire ................................................. L. nipensis.
                                     11.  Corollas only sparsely lepidote, ± cylindrical or long
                                            to short-urceolate; capsules 2.5-5(-6) mm wide;
                                            calyx lobes 0.7-2.5 mm long;  leaves irregularly to
                                            obscurely toothed or notched, or entire.
                                            12.  Corollas shortly urceolate, 2.5-5 by 2.5-4 mm,
                                                   usually nearly as wide as long; underground
                                                   rhizomes often produced; Mexico ..... L. squamulosa.
                                            12.  Corollas ± cylindrical or occasionally long-
                                                   urceolate, (3-)4-8 by 2-5 mm, always clearly
                                                   longer than wide;  underground rhizomes not
                                                   produced; West Indies.
                                                   13.  Leaves with the secondary veins on adaxial
                                                          surface more prominent than tertiary and higher
                                                          order veins, usually clearly joined together in
                                                          series of arches, the abaxial surface with
                                                          secondary veins ± visible and connected together
                                                          [inner periclinal walls of adaxial leaf epidermis
                                                          strongly lignified and thickened];  Cuba ..........
                                                          ..........................................................  L. affinis.
                                                   13.  Leaves with the secondary veins on adaxial
                                                          surface not much more prominent that tertiary
                                                          or higher order veins, so not clearly joined
                                                          together in series of arches, or all veins ±
                                                          obscure, the abaxial surface with secondary
                                                          veins obscure to slightly visible, interconnections
                                                          nearly always obscure [inner periclinal walls of
                                                          adaxial leaf epidermis lignified, but no thicker
                                                          than other epidermal walls];  Hispaniola, Puerto
                                                          Rico, St. Thomas.
                                                          14.  Leaves with the apex acuminate to acute or
                                                                 rounded-truncate, the abaxial surface with
                                                                 tertiary and higher order veins visible and
                                                                 slightly reticulate; capsules ellipsoid to widely
                                                                 so, 3.5-6 mm wide;  St. Thomas ...............
                                                                 ................................................ L. rubiginosa.
                                                          14.  Leaves with the apex acute to truncate, the
                                                                 abaxial surface with tertiary and higher order
                                                                 veins obscure to visible and very slightly
                                                                 reticulate;  capsules ovoid or ellipsoid to sub-
                                                                 globose, 2.5-4.5(-5) mm wide; Hispaniola
                                                                 or Puerto Rico.
                                                                 15.  Low spreading shrub, to 0.5 m tall;
                                                                        capsules subglobose or globose to
                                                                        short-ovoid, 3-4 mm long and wide,
                                                                        4- and 5-valved; leaves strongly
                                                                        coriaceous, ca. 0.5-0.6 mm thick,
                                                                        ± densely lepidote beneath ........ L. alpina.
                                                                 15.  Erect shrub to small tree, to 1.5-7 m tall;
                                                                        capsules ovoid to ellipsoid, 3-6.5 by
                                                                        2.5-4.5(-5) mm, almost exclusively
                                                                        5-valved; leaves less coriaceous, ca.
                                                                        0.3-0.4 mm thick, only sparsely or
                                                                        moderately lepidote beneath ... L. truncata.
     2.  Lamina completely lacking unicellular hairs on abaxial surface (although they may
          be present on midvein or some secondary veins).
          16.  Margin of apical half of leaves definitely and ± irregularly toothed.
                 17.  Flowers exclusively 4-merous; lamina rounded to widely cuneate or
                        slightly cordate at base, thinly coriaceous, ca. 0.15-0.2 mm thick, ca.
                        2-5.5 cm wide .................................................................. L. maestrensis.
                 17.  Flowers 5- (4-) merous; lamina narrowly to widely cuneate
                        (to rounded) at base, moderately to strongly coriaceous, ca. 0.2-
                        0.45 mm thick, ca. 1-4 cm wide (but if flowers 4-merous then only
                        1-3 cm wide).
                        18.  Corollas shortly urceolate, 3.5-5 mm long, about as wide as long,
                               usually pink; capsules subglobose to globose or nearly so,
                               moderately to densely pubescent; young stems glabrous to sparsely
                               pubescent .......................................................................... L. alainii.
                        18.  Corollas ± cylindrical, 4.5-10 mm long, longer than wide, white
                               to pink-tinged at mouth; capsules usually ellipsoid to ovoid, usually
                               only sparsely pubescent; young stems glabrous to densely pubescent.
                               19.  Young stems thick, 2-3.5 mm wide near base of flowering or
                                       fruiting branches, densely pubescent; capsules 3-5 mm wide,
                                       5-valved; leaves coriaceous, ca. 0.35-0.45 mm thick ............
                                       ......................................................................... L. tuerckheimii.
                               19.  Young stems thinner, 1.2-2.3 mm wide near base of flowering
                                      or fruiting branches, usually nearly glabrous or only sparsely
                                      pubescent; capsules 1.7-3.5(-4.5) mm wide, 5- and/or
                                      4-valved;  leaves thinner, ca. 0.2-0.35 mm thick .........  L. stahlii.
          16.  Margin of apical half of leaves entire to sinuous or very obscurely toothed.
                 20.  Capsules narrowly ovoid, 1.7-3(-3.5) mm wide,  mainly 4-valved
                        (although rare individuals with mainly 5-valved capsules occur in L.
                        myrtilloides); corollas 2.5-4.5 mm long;  petioles 1.5-6 mm long.
                        21.  Leaves often uniformly small on strongly ascending branches,
                               often obovate, to elliptic or widely elliptic, secondary veins ±
                               irregular and often very obscure on abaxial surface, apex rounded
                               to truncate; pedicels 2.5-11 mm long ........................  L. myrtilloides.
                        21.  Leaves not uniformly small on strongly ascending branches,
                               ± elliptic to ovate, secondary veins ± regular and apparent on
                               abaxial surface, apex acuminate or acute to rounded or truncate;
                               pedicels 1.5-4.5 mm long.
                               22.  Capsules long-ovoid, 2.5-5 mm long, length/width quotient
                                      of valves 3-4;  young twigs sparsely to densely pubescent;
                                      corollas 3-4.5 mm long ..................................  L. trinidadensis.
                               22.  Capsules very shortly ovoid, 2.5-4.3 mm long, length/width
                                      quotient of  valves 2-3.3; young twigs essentially glabrous;
                                      corollas 2.5-4 mm long .......................................  L. octandra.
                 20.  Capsules ellipsoid or ovoid, to subglobose, (2.5-)3-6 mm wide,
                        mainly 5-valved (usually 4-valved in L. ekmanii, which has ovoid
                        capsules 4-4.5 mm wide); corollas 2.5-7 mm long; petioles 1.5-15 mm
                        long.
                        23.  Corollas shortly urceolate, 2.5-5 x 2.5-4 mm, as wide as long or
                               nearly so; capsules subglobose to globose or ovoid, 2.5-5 mm
                               long and wide.
                               24.  Corollas usually pink; leaves coriaceous, ca. 0.34-0.44 mm
                                      thick, not flexible or only slightly so when dried, the margin
                                      usually obscurely toothed or notched (or clearly toothed),
                                      the apex acute to rounded or truncate but never acuminate,
                                      the scales of abaxial surface ± widely spaced; neither
                                      elongated woody burl nor rhizomes present .............. L. alainii.
                               24.  Corollas white; leaves thinner, ca. 0.17-0.26 mm thick,
                                      more flexible, the margin usually entire, rarely obscurely
                                      toothed, the apex acuminate or acute to rounded, the scales
                                      of abaxial surface widely spaced to overlapping; elongated
                                      woody burl and often rhizomes present ........... L. squamulosa.
                        23.  Corollas cylindrical to long-urceolate, 4-7 x 2-4.5 mm,
                               always longer than wide; capsules ovoid to ellipsoid,
                               3.5-9 x 2.5-6 mm.
                               25.  Calyx lobes 1.3-2.5(-3) mm long;  corollas long-urceolate;
                                      capsules 3.5-9 x 3.5-6 mm; leaves rounded or truncate to
                                      acute or nearly so at apex, at least basal portion of abaxial
                                      midvein sometimes with unicellular hairs; filaments usually
                                      with 2 minute spurs near junction with anthers.
                                      26.  Capsules ± ovoid with straight-sided valves; pedicels
                                             8-30 mm long; leaves with abaxial surface sparsely
                                             lepidote, with usually 10-40 ± entire-margined scales,
                                             the petiole 1.5-5(-9) mm long.
                                             27.  Leaves to ca. 7 cm long, usually slightly to strongly
                                                    recurved, often with midvein and/or secondary veins
                                                    depressed, the abaxial side with tertiary veins much
                                                    less prominent than secondary, obscure to slightly
                                                    reticulate; apex usually rounded ................ L. obtusa.
                                             27.  Leaves to ca. 3.5 cm long, flat, veins not depressed,
                                                    the abaxial side with tertiary veins nearly as
                                                    prominent as secondary, strongly reticulate
                                                    pattern; apex acute to rounded ............... L. longipes.
                                      26.  Capsules ± ellipsoid to ovoid with usually convex valves;
                                             pedicels 4-12 mm long; leaves with abaxial surface
                                             moderately lepidote, with usually 60-140 ± irregularly
                                             margined scales, the petiole 4-15(-18) mm long.
                                             28.  Twigs densely pubescent;  flowers 5-merous;
                                                    capsules 4.5-8.5 mm long ................ L. macrophylla.
                                             28.  Twigs essentially glabrous; flowers mainly 4-merous;
                                                    capsules 3.5-5 mm long .......................... L. ekmanii.
                               25.  Calyx lobes 0.6-2 mm long; corollas usually ± cylindrical;
                                      capsules 3.5-6 x 2-4 mm; leaves acute or acuminate to
                                      rounded or truncate at apex, abaxial midvein lacking
                                      unicellular hairs; filaments lacking spurs.
                                      29.  Young twigs usually only sparsely pubescent; leaves
                                              with length/width quotient of 1.5-2(-3.5), margin
                                              obscurely and irregularly toothed to ± entire,
                                              secondary veins sometimes slightly depressed;
                                              corollas 4-6 mm long ..............................  L. rubiginosa.
                                      29.  Young twigs usually moderately pubescent; leaves
                                             with length/width quotient of 2-4, margin ± entire,
                                             secondary veins almost never depressed; corollas
                                             (4-)4.5-7 mm long ................................... L. jamaicensis.

     This is a version of the taxonomic treatment of the neotropical species of Lyonia (Ericaceae) by Walter S. Judd, modified from "Ericaceae--Part II. The Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae, and Vaccinioideae p.p.)."  The full treatment including specimen citations may be see in Flora Neotropica Monograph 66: 222-294 (Judd, 1995c).  This synthesis is published with permission of The New York Botanical Garden and Walter S. Judd.

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