Lycianthes rzedowskii E.Dean, Novon 4: 327, 1994

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

41 Lycianthes rzedowskii E.Dean, Novon 4: 327, 1994 Fig. 91

Type.

México. Michoacán: Mpio. Charo, along hwy 15, 20 rd km E of Morelia, just E of Pontezuelas, 2165 m, 13 Nov 1991, E. Dean 322a (holotype: UC [UC1797879]; isotypes: DAV [DAV158015], NY [00687931], XAL [XAL0106679]).

Description.

Perennial herb from fusiform storage roots, usually erect, often recumbent with age, 0.17-1.1 m tall, dying back each season. Indument of white, uniseriate, multicellular, simple or dendritically branched, eglandular, spreading to appressed, sometimes crisped, trichomes, 0.1-1.5 (2) mm long. Stems green to reddish-purple, glabrous to sparsely pubescent, usually compressed and ribbed when dried in a plant press, somewhat woody with age, especially at base of plant; first stem 7-90 cm long to first inflorescence, the internodes (6) 10-21; first two sympodial branching points usually dichasial, usually followed by monochasial branching, this branching usually limited. Leaves simple, those of the upper sympodia usually paired and unequal in size, the larger ones with blades (2.5) 5-10 (15) × 1-6 cm, the smaller ones with blades 1/4 to 3/4 the size of the larger, the leaf pairs similar in shape, the blades ovate, elliptic, or obovate, chartaceous, sparsely to moderately pubescent, the primary veins 5-7 on either side of the midvein, the base truncate or cuneate, attenuate onto the petiole, sometimes oblique, the margin entire, usually irregularly undulate, the apex acuminate, the petioles of larger leaves winged and poorly defined, 0.1-2.8 cm long, sometimes absent. Flowers solitary, axillary, oriented horizontally, and somewhat nodding; peduncles absent; pedicels 19-86 mm and erect in flower, 30-110 mm long and deflexed in fruit, glabrous to moderately pubescent; calyx 3-6 mm long, 3-6.5 mm in diameter, campanulate, glabrous to moderately pubescent, the margin truncate, with 10 knob-like to linear, slightly spreading or erect appendages 1-7.25 mm long emerging ca. 1 mm below the calyx rim; fruiting calyx enlarged, 2-10 mm long, 5-14.5 mm in diameter, the appendages stout, stiff, remaining appressed to fruit or somewhat spreading, often broken, 1-7.5 mm long; corolla 1-2.5 cm long (2-4.7 cm in diameter), rotate in orientation, mostly entire in outline (with shallow notches), with abundant interpetalar tissue, white (rarely tinged lilac), with violet stripes near the major veins adaxially, green near the major veins abaxially, usually glabrous; stamens unequal, the filaments of three lengths, the two shortest filaments 1-4 mm long, the two medium filaments 2-4 mm long, the one long filament 2.5-6.25 mm long, the length of the long filament always less than 2 times that of the medium filaments, glabrous, the anthers 3-5.5 mm long, lanceolate to elliptic, free of one another, yellow, glabrous, poricidal at the tips, the pores round to oval, dehiscing distally, not opening into longitudinal slits; pollen grains dicolporate; pistil with glabrous ovary, the style 7-11 mm, linear, straight to slightly curved, the stigma round, rarely somewhat lobed. Fruit a berry, usually remaining attached to calyx at maturity, pendent, 19-75 mm long, 8-19 mm in diameter, turbinate, elongate, the exocarp dull light purple to black at maturity (green with light or dark longitudinal lines when immature), glabrous, the mesocarp dark purple, soft and juicy, lacking sclerotic granules, the placental area light purple, powdery in texture. Seeds 3-38 per fruit, 3.5-5 × 3.2-4.7 mm, not compressed, depressed obovate, ridged and blistered along one side, black in color, the surface reticulum rough in texture with loose serpentine pattern with deep luminae.

Chromosome number.

2n = 24, Dean 212, 317, 336 ( Dean 2004).

Distribution and habitat.

Mexico ( México, Michoacán, Morelos) in oak, oak-pine, pine-oak, and fir forests, often on forested slopes near drainages, on volcanic soils, 1794-2645 m in elevation (Fig. 92 ).

Common names and uses.

Mexico. Chilillo ( Dean 2004).

Phenology.

Flowering specimens have been collected June to October; specimens with mature fruits have been collected in late November and December. The first author has observed in the field that the corollas open in very early morning and closed in the late morning. The pollen of this species has a sweet, powdery fragrance.

Preliminary conservation status.

Lycianthes rzedowskii is a locally common species of central/western Mexico, represented by 43 collections and occurring in six protected areas. Unfortunately, the habitat of this species is vulnerable due to urban development. The conservation status of this species was assessed by Anguiano-Constante et al. (2018) and their preliminary assessment was Least Concern. The EOO is 24,120.227 km2, and the AOO is 160 km2. Based on the IUCN (2019) criteria, the preliminary assessment category is now Endangered (EN).

Discussion.

Lycianthes rzedowskii may be confused with L. acapulcensis and L. ciliolata . It can be distinguished from those species by the many internodes on its first stem, the usually poorly developed sympodial branching in flowering plants, smooth, white (rarely pale lilac) corollas, and broad sweetly scented anthers with terminal, round anther pores. In addition, one of the best ways to distinguish L. rzedowskii from the other two species is to look at the relative lengths of the stamen filaments. In L. rzedowskii the length of the longest filament is never more than twice that of the medium-short filaments, while in the other two species, the length of the longest filament is almost always more than twice that of the medium-short. Lycianthes rzedowskii may hybridize with L. acapulcensis and L. starbuckii E.Dean where they occur together ( Dean 2004).

Representative specimens examined.

Mexico. México: Avandaro, Cerro Gordo, 19.1142, -100.1341, 2301 m, 22 Jun 2011, L. Corral 1801 (MEXU). Michoacán: San Miguel Chichimequillas La Mesa, 19.4065, -100.3631, 2018 m, 15 Jul 2007, L. Corral 376 (MEXU). Morelos: Sierra de Morelos, Cuernavaca, [18.9794, -99.2841], 2050 m, 26 Jul 1969, Hinton 17221 (NY).

Figures

Figure 91. Image of herbarium specimen of L. rzedowskii, Dean 320 (DAV). Image used with permission of the UC Davis Center for Plant Diversity.

Figure 92. Map of geographic distribution of L. rzedowskii based on herbarium specimen data.