Lycianthes rafatorresii E. Dean, 2020

Dean, Ellen, Poore, Jennifer, Anguiano-Constante, Marco Antonio, Nee, Michael H., Kang, Hannah, Starbuck, Thomas, Rodrigues, Annamarie & Conner, Matthew, 2020, The genus Lycianthes (Solanaceae, Capsiceae) in Mexico and Guatemala, PhytoKeys 168, pp. 1-333 : 1

39 Lycianthes rafatorresii E. Dean sp. nov. Fig. 88

Type.

México. Oaxaca: Distrito Juchitán, Mpio. Santa María Chimalapa, San Antonio Nuevo Paraiso, a 2 km en línea recta al W, en Cerro Camedor, 17.1444, -94.3577, C. Perret 352 (holotype: MEXU [acc. # 1143589]; isotypes: IEB [acc. # 210462, acc. # 209686], SERO).

Diagnosis.

Very similar to Lycianthes multiflora Bitter of Central America, L. sideroxyloides of Mexico and Central America, and L. armentalis of the Yucatán Peninsula. Differing from those species in having the following combination of characters: multangulate-stellate (not geminate-stellate) trichomes with straight (not crisped) trichome rays, branching not widely divaricate, inflorescences that are not restricted to the last few terminal, leafless, sympodial units of the plant, calyx appendages with a widened bulbous apex (rather than acute), stellate corollas divided one quarter to approximately half way to the base with abundant interpetalar tissue, unequal stamens, and few, large fruits, 8-15 mm in diameter with 40-100 seeds per fruit, the seeds usually slightly notched on one side.

Description.

Shrub (sometimes scandent), treelet, to vine, 1-5 (20) m tall. Indument of off-white, grey, pale yellow, or yellow-orange, uniseriate, multicellular, sessile to short-stalked, multangulate-stellate, eglandular, spreading trichomes 0.1-0.25 mm long, 0.25-0.75 mm in diameter, the rays 5-8 per whorl, usually straight (not crisped), not rebranched, the center of the trichome where the rays meet sometimes enlarged and spherical, the trichomes of the adaxial leaf surface often sessile and appressed to the leaf surface. Stems light green when young, (drying tan to brown), moderately to densely pubescent (appearing like dense felt), slightly compressed and ribbed when dried in a plant press, becoming brown and woody with age; upper sympodial branching points a mixture of monochasial and dichasial branching (often monochasial), the branching not divaricate. Leaves simple, the leaves of the upper sympodia usually paired, the pairs unequal in size, the larger ones with blades 4.5-13 × 2.5-6 cm, the smaller ones with blades 1.5-7.6 × 1-3.8 cm, the leaf pairs similar in shape, the blades ovate to elliptic, chartaceous to subcoriaceous, sparsely to moderately pubescent, the base cuneate (sometimes widely so), rarely rounded, sometimes oblique, the margin entire, usually irregularly undulate, the apex acute to acuminate, the petiole 0.3-2.5 cm long, the larger leaf blades with 4-6 primary veins on each side of the midvein. Flowers solitary or in groups of 2-6 (-10), axillary, oriented horizontally; peduncles usually absent, sometimes a small pad forming with numerous pedicel scars, to 2 mm long; pedicels 4-10 mm long and erect in flower, to 17 mm long and erect in fruit, moderately to densely pubescent; calyx 2-4 mm long, 3-4 mm in diameter, campanulate, moderately to densely pubescent, the margin truncate, with 10 erect linear appendages with widened, bulbous apex, 1-4 mm long, emerging 0.5-1 mm below the calyx rim, the rim membranaceous and papery; fruiting calyx enlarged, widely bowl-shaped to rotate, 2-4 mm long, 6-10 mm in diameter, the appendages to 5 mm long; corolla 0.7-1.5 cm long, orientation of open corolla unknown (most likely campanulate or rotate), shallowly stellate in outline, divided 1/4 to 1/2 of the way to the base (the division increasing by tearing as the flower ages), with abundant interpetalar tissue, the adaxial side white, glabrous, the abaxial side of the lobes of unknown color, densely pubescent with multangulate-stellate, appressed trichomes; stamens unequal, straight, the four short filaments 0.5-1 mm long, the one long filament 2-3.5 mm long, glabrous, the anthers 4-5 mm long, lanceolate, narrowed at the tip, free of one another, yellow, sparsely pubescent on the inner face, poricidal at the tips, the pores ovate, terminal, dehiscing distally, not opening into longitudinal slits; pistil with glabrous ovary, the style 7-8 mm long, linear, straight, glabrous, the stigma oblong, decurrent down two sides. Fruit a berry, 8-15 mm long, 8-15 mm in diameter, globose, red-orange when mature, glabrous, lacking sclerotic granules. Seeds 40-100 per fruit, 2-3 × 2-3 mm, flattened, circular to depressed ovate in outline, sometimes shallowly indented on one side (<0.5 mm), thickened on the margin, yellow-orange to orange-brown, the margin darker in color than the center, the surface reticulum nearly smooth in the center with indistinct serpentine pattern and shallow luminae, the luminae much deeper on the margin.

Chromosome number.

Unknown.

Distribution and habitat.

Mexico, Caribbean slope (Oaxaca, Puebla, Veracruz), in tropical moist forest, tropical dry forest, and cloud forest, in both primary forest and disturbed areas, such as coffee plantations and along roadsides, often growing with Quercus or Liquidambar , sometimes on steep slopes or along drainages, sometimes on limestone, 200-1600 m in elevation (Fig. 89 ).

Common names and uses.

Mexico. Oaxaca: paniui poj (Zoque) ( Hernández G. 1234).

Phenology.

Flowering specimens have been collected March through September; specimens with mature fruits have been collected May through November. The corollas on specimens of this species are usually closed, indicating that the corollas are open for only a short time period during the day, most likely in morning.

Preliminary conservation status.

Lycianthes rafatorresii is a rare shrub with a discontinuous distribution represented by 22 collections, and it is only present in one protected area (Los Tuxtlas). The size of the EOO area (51,517.851 km2) suggests a preliminary conservation assessment of Least Concern (LC). In contrast, the size of the AOO area (76 km2) suggests an Endangered (EN) status.

Etymology.

This species is named for Mexican botanist Rafael Torres Colín (Rafa), an expert on the flora of Oaxaca, who led us into the field in 2017, when we attempted to locate this species.

Discussion.

Lycianthes rafatorresii is a Mexican endemic of the Caribbean slope of Oaxaca, Puebla, and Veracruz. Morphologically, it is close to L. multiflora Bitter of Central America (which does not occur in Guatemala or Mexico), and it has been misidentified as L. sideroxyloides (with which it overlaps in distribution) and L. armentalis (with which it does not overlap) ( Nee 1986). It differs from L. multiflora in having straight to curved rays on the trichomes (rather than crisped rays in L. multiflora ), having the inflorescences and fruits on leafy stems that are not restricted to the last few terminal sympodial units of the plant (rather than having flowers and fruits on mostly leafless terminal sympodia (so that they appear to be in a large panicle), having calyx appendages with a widened bulbous apex (rather than acute appendages), and having stellate corollas (rather than entire corollas). Lycianthes rafatorresii differs from L. sideroxyloides in lacking geminate-stellate trichomes, by having a corolla divided just half way to the base (or less) with abundant interpetalar tissue (versus a deeply stellate corolla with scant interpetalar tissue), by having unequal stamens (versus equal stamens), and by having fewer, larger mature fruits (8-15 mm in diameter versus 2-7 mm in diameter in L. sideroxyloides ). It differs from L. armentalis in lacking widely divaricate branching, having appendages with a widened bulbous apex (versus acute appendages), having more seeds per fruit (40-100 in L. rafatorresii versus 20-30 in L. armentalis ), occurring at higher elevations (to 1600 m in L. rafatorresii versus to 500 m in L. armentalis ), and not occurring in the lowlands of the Yucatán Peninsula. More field study of L. rafatorresii is needed to better separate it from these similar species and understand its distribution, which currently does not appear to be continuous. Attempts by the first and third authors to locate this species in the field in Oaxaca in 2017 were unsuccessful.

Representative specimens examined.

(full list of paratypes in Appendix I). Mexico. Oaxaca: Dto. de Ixtlán, 3 km al S de Metates, carr. Tuxtepec-Oaxaca, [17.5872, -96.5065], no elevation, 10 Sep 1985, R. Torres C. 7270 (MO). Puebla: Limonateno, [19.9110, -97.3076], 1000 m, 12 May 1970, F. Ventura A. 1077 (IEB). Veracruz: Bastonal, 3-5 km adelante, camino a la Sierra de Santa Marta, 18.40, -94.95, 25 Nov 1985, G. Castillo-Campos 4417 (XAL).

Figures

Figure 88. Image of herbarium specimen of L. rafatorresii, Perret 352 (MEXU). Specimen used with permission from the Herbario Nacional de Mexico, Universidad Autonoma de Mexico.

Figure 89. Map of geographic distribution of L. rafatorresii based on herbarium specimen data.