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

Synonyms:

Lyonia acutifolia Urb. & Ekman, Lyonia angulata Urb. & Ekman, Xolisma longelaminata Sleumer, Lyonia costata Urb., Xolisma costata (Urb.) Small, Lyonia rubiginosa subsp. costata (Urb.) Borhidi, Lyonia rubiginosa var. costata (Urb.) Judd, Lyonia darrasiana Urb. & Ekman, Lyonia longelaminata (Sleumer) Jiménez

Description:

Variety Description - Erect shrub to moderate-sized tree to 4(-10) m tall. Twigs subglabrous to slightly pubescent. Leaf blades 2-6(-8.5) × 0.7-3(-5) cm; margin apically strongly to obscurely and irregularly toothed, basally entire to obscurely toothed; adaxial surface with 3° and higher-order veins faintly visible to obscure, usually at least some 2° veins visible and slightly to moderately depressed. Pedicels slender, 5-10 mm long. Flowers 4-5-merous; corolla (5.5-)6-8.5 × (2-)2.5-4 mm. Capsules (3-)3.5-6 × 1.7-3.5 (-4) mm.

Discussion:

Lyonia stahlii is divided into two geographically isolated varieties which may be differentiated on characters such as degree of depression of secondary veins, prominence of marginal serrations, and corolla size (see key). The two taxa are recognized at the level of variety because they differ only in a few characters of leaf morphology and in some slight size differences in the flowers and/or fruits- characters that are overall quite variable among the West Indian species.

Lyonia stahlii is probably most closely related to Lyonia alainii, L. tuerckheimii, L. rubiginosa, and L. truncata. Lyonia stahlii differs from L. alainii in its ellipsoid to ovoid and more sparsely pubescent capsules, white, cylindrical corollas, and less coriaceous leaves. The species is easily distinguished from L. tuerckheimii by its slender and usually only sparsely pubescent twigs, different habit, less robust capsules, and thinner leaves with the secondary veins often depressed. Lyonia stahlii differs from L. truncata and L. rubiginosa in the lack of unicellular hairs on the abaxial leaf surfaces (see also key). Lyonia stahlii var. costata is elevationally (and ecologically) isolated from L. tuerckheimii. It is found in low-elevation Pinus occidentalis forests, thickets, or moist cloud forests up to ca. 2100 m in the Cordillera Central and ca. 2000 m in the Massif de la Selle, while L. tuerckheimii occurs at elevations above ca. 2000 m in the ecologically quite different, high-elevation Pinus occidentalis forests. (In the Massif de la Hotte, L. stahlii has been collected up to 2300 m elev.; L. tuerckheimii does not occur in that mountain range.) Variety costata is also altitudinally isolated from L. truncata; it occurs at elevations above ca. 1600 m in the Cordillera Central and above ca. 1600 m in the Massif de la Selle, while L. truncata has been collected at up to 1200 m in the Cordillera Central and to about 1700 (-1800) m in the Massif de la Selle. Lyonia stahlii var. costata seems to be rare in the Sierra de Baoruco, where it has been collected only above Los Arroyos (in Lomas del Toro) near the Haitian border at an elevation of ca. 1800 m, well above any known collection of L. truncata in this region. Variety costata is geographically isolated from L. alainii as var. stahlii is from all related taxa.

Lyonia stahlii var. stahlii is also similar to L. jamaicensis (a species endemic to Jamaica), from which it can be distinguished by its leaves being usually about twice as long as wide and sometimes more strongly toothed and having secondary veins sometimes slightly depressed.

Within Lyonia stahlii var. costata there is a great variation in leaf shape, size, apex, and secondary-vein depression, as well as in prominence of the network of tertiary and higher-order veins of the abaxial surface. This has lead to the description of many species that can not be maintained (Judd, 1981). It is interesting to note that flowers of populations in the Massif de la Hotte are characteristically 4-merous, while those of the Massif de la Selle are usually mixed 4- and 5-merous, and those of the Cordillera Central, Massif du Nord, Sierra de Neiba, and Monteada Nueva are chiefly 5-merous. No other morphological characteristics studied are correlated with this variation in number of floral parts.

Lyonia stahlii var. stahlii is also extremely variable in the size, shape (narrowly elliptic to nearly orbicular), apex type (acute to truncate), margin (entire to strongly toothed), and venation (obscure to visible and slightly depressed) of its leaves. This variation probably results from both genetic and environmental effects. Plants in exposed, windswept conditions tend to have smaller, more entire-margined leaves, while shade leaves and leaves on rapidly growing sucker shoots are usually quite large. Plants with very different leaf shapes, however, can be found growing side by side under similar environmental conditions. In addition, the leaves increase in size (and often change shape) as the plant matures. Shading may also affect the luster and prominence of secondary veins and the angle at which the leaves are held in relation to the stem.

Shrubs of Lyonia stahlii readily sucker from the base, especially after disturbance; the leaves of young shoots are often bright red due to the presence of anthocyanins, producing a strikingly beautiful contrast with the older, deep green leaves. Seedlings characteristically have very small, acute to acuminate, and more or less strongly toothed leaves.

Distribution:

Dominican Republic South America| Haiti South America|