Monographs Details: Lyonia tinensis Urb.
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)
Scientific Name:Lyonia tinensis Urb.
Synonyms:Xolisma pseudotinensis Sleumer, Xolisma tinensis (Urb.) Small, Lyonia pseudotinensis (Sleumer) Jiménez, Lyonia apiculata (Sleumer) Jiménez
Description:Species Description - Evergreen, usually erect shrub or small tree to 5 meters tall, with grayish, longitudinally furrowed bark; twigs slightly angled, slender, sparsely to densely lepidote, otherwise glabrous to sparsely pubescent; buds ovoid, 1-2 × 0.8-1.3 mm, lepidote. Leaf blades ovate to elliptic, 1.7-3.5(-4.7) × 0.9-1(-2.8) cm, flat to moderately recurved, coriaceous, ca. 0.32-0.45 mm thick; base cuneate to rounded; apex slightly acuminate to truncate; margin plane to re volute, apical portion strongly to obscurely and irregularly toothed (nearly entire), basal portion strongly toothed to entire; venation brochidodromous, 3° veins ± reticulate; abaxial surface lepidote but scales usually quickly deciduous, moderately to sparsely pubescent on basal portion of midvein, 2° and 3° veins obscure to slightly visible (few 2° depressed); abaxial surface sparsely to moderately lepidote, otherwise densely pubescent, with all veins raised, forming dense and fine reticulum, often not visible without magnification; scales usually light brown, often becoming whitish, persistent, less commonly deciduous, ca. 0.08-0.26 mm in diam., erose; petiole 2-4.5 mm long, lepidote, otherwise adaxially pubescent; flower buds ± intermixed with vegetative buds. Inflorescences fasciculate, ca. 3-10-flowered; pedicels clearly articulated with calyx, slender, (2.5-)3-7.5 mm long, lepidote, otherwise glabrous; bracteoles ± opposite, basal, narrowly triangular, 1-1.3 mm long; floral bracts to ca. 2 mm long. Flowers (4-)5-merous; calyx lobes triangular, with acuminate apices, 0.7-1.5 × 0.6-0.9 mm, adaxial side sparsely pubescent at margins and near apex, abaxial side lepidote, otherwise glabrous; corolla cylindrical, white, 4-5 × 2-3 mm, abaxially sparsely lepidote; filaments roughened, 2.5-3 mm long, unappendaged; anthers 0.8-1 mm long; ovary lepidote, otherwise pubescent, placentae subapical. Capsules usually narrowly ovoid, 3.5-6 × 1.5-3 mm, apex usually slightly constricted, slightly lepidote, otherwise sparsely pubescent, the pale, very thick sutures separating as unit from adjacent valves; seeds 1-2.9 mm long.

Discussion:Lyonia tinensis is closely related to L. urbaniana (see above for differences), L. microcarpa, and L. truncata. It can be readily distinguished from L. microcarpa by leaves that are longer in relation to their width and that have brownish scales and by its wider, 5-merous capsules. Lyonia tinensis differs from L. truncata in its often more strongly toothed leaves with a densely raised-reticulate network of veins on the abaxial surface, its narrower capsules constricted at the apex, and its often smaller flowers. Lyonia tinensis is geographically isolated from L. microcarpa and L. truncata var. truncata since both of these taxa occur only in the Massif de la Selle-Sierra de Baoruco; it is isolated by habitat and elevational range from L. urbaniana and L. truncata var. montecristina. Lyonia truncata var. montecristina is found at ca. 100-1250 m. elev., while L. tinensis occurs at 1100-1700 m.

The leaves of a single plant can vary from acute to quite strongly truncate at the apex, or revolute to plane at the margin, and there is sometimes marked variation in width or length of leaves between different individuals in the same population (see Marcano 5761). Occasional plants are only very slightly pubescent on the abaxial leaf surface. Ultimate branchlets can be rigidly ascending to arching, depending on the vigor and habitat of the plant.
Distribution:Dominican Republic South America|