Lycianthes peduncularis (Schltdl.) Bitter, Abh. Naturwiss. Verein Bremen 24 [preprint]: 416. 1919

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

34 Lycianthes peduncularis (Schltdl.) Bitter, Abh. Naturwiss. Verein Bremen 24 [preprint]: 416. 1919 Fig. 78

Solanum pedunculare Schltdl., Linnaea 19: 305. 1847. Type: Germany. Leipzig Botanical Garden, 1842, G. Kunze s.n. (neotype designated by Dean 2004, pg. 416: W [acc. # 292213] see discussion in commentary below).

Type.

Based on Solanum pedunculare Schltdl.

Description.

Perennial herb from large fusiform storage roots, prostate to decumbent, to 0.25 m tall and 0.5 m in diameter, dying back each season. Indument of white, uniseriate, multicellular, simple (rarely a few dendritically branched), curved, eglandular, usually appressed-ascending trichomes, 0.1-1.25 mm long. Stems green with darker green and purple striations, moderately pubescent, much compressed upon drying in a plant press, usually nonwoody; first stem 0.5-7 cm long to the first inflorescence, the internodes 4-6 (10); first sympodial branching point dichasial, followed by a mixture of monochasial and dichasial branching, this branching extensive, usually resting on the soil surface. Leaves simple, those of the upper sympodia usually paired and unequal in size, the larger ones with blades (1) 1.5-9 (14) × (0.5) 0.7-4 (7) cm, the smaller ones with blades 1/8-3/4 the size of the larger, the leaf pairs similar in shape, the blades ovate, elliptic, or obovate, thick chartaceous, sparsely to moderately pubescent, the primary veins 3-5 on either side of the midvein, the base truncate to cuneate, short to long attenuate onto the petiole, sometimes oblique, the margin entire, usually slightly undulate, the apex short acuminate to rounded, the petioles winged and poorly defined, to 2 cm long, sometimes absent. Flowers solitary, axillary, oriented horizontally; peduncles absent; pedicels (20) 30-115 mm and erect in flower, 33-180 mm long, deflexed and undulate in fruit, sparsely to moderately pubescent; calyx (1.5) 2-3.5 (4.5) mm long, (2.5) 3.25-4.5 mm in diameter, broadly cupulate, moderately pubescent, the margin truncate, with 10 linear, spreading to reflexed appendages (0.5) 1-4.5 (6) mm long emerging ca. 0.5 mm below the calyx rim; fruiting calyx enlarged, 5.5-12.5 mm long, (9.5) 12-25 mm in diameter, the teeth recurved, often making a complete loop, often broken, 1-12.5 mm long; corolla 1.1-2.5 cm long (2.2-4.9 cm in diameter), rotate in orientation, mostly entire in outline (with shallow notches), with abundant interpetalar tissue, white to lilac, with violet stripes along the major veins adaxially, green and moderately pubescent near the major veins abaxially; stamens unequal, curved, the filaments of three different lengths, the two shortest filaments (1.25) 1.75-3 (4) mm long, the two medium filaments (1.5) 2.25-3.75 (5) mm long, the one long filament 2.5-5.5 (8.5) mm long, the length of the long filament 1.2-1.8 (2.5) times that of the medium-short filaments, glabrous; anthers (2.5) 3-5.5 (6.5) mm long, elliptic to ovate, rarely lanceolate or oblong, free of one another, yellow, glabrous, poricidal at the tips, the pores ovate to slit-like, dehiscing distally or toward the style, not opening into longitudinal slits; pollen tricolporate; pistil with glabrous ovary, the style 6-10.5 (12) mm, linear, curved downward, the stigma round to shallowly lobed. Fruit a berry, remaining attached to the calyx at maturity (the fruit matures while lying on the ground), 9-24 mm long, 9-26 mm in diameter, round to ovoid, the exocarp green with purple or black lines (becoming yellowish in age), the mesocarp thin, green and juicy, with profuse sclerotic granules, 32-83 per fruit, round to angular, yellow, the placental area narrow, greenish-white, juicy. Seeds (12) 20-100 (143) per fruit, (2.5) 3-4 × 2.2-3.1 (3.7) mm, not compressed, oblong to depressed-ovate, smooth, ridged, dark brown to black, surface reticulum with loose serpentine pattern with deep luminae and microscopic fibrils protruding from the cell walls.

Chromosome number.

2n = 24, Dean 303 ( Dean 2004)

Distribution and habitat.

Mexico (Guanajuato, Hidalgo, México, Oaxaca, Puebla, Querétaro), in xerophilous scrub, rarely pine/juniper woodland, on rocky, limestone soils, often near a drainage or in a wash or canyon, often on an eroded floodplain, sometimes within or at the sides of agricultural fields or pastures, 770-2500 m in elevation (Fig. 79 ).

Common names and uses.

Mexico. Trompeta, berenjena, chichi de perra, ojo de venado, tonchichi, tomatillo del monte ( Dean 2004).

Phenology.

Flowering specimens have been collected June through August; specimens with mature fruits have been collected August to October. The first author has observed that the corollas open in the very early morning and close by noon. The pollen has a sweet scent. Solitary bees in the genera Exomalopsis and Ptiloglossa visit this species ( Dean 2001).

Preliminary conservation status.

Lycianthes peduncularis is a common species ranging from northern to southern Mexico, represented by 64 collections and occurring in two protected areas (Yagul and Tehuacán-Cuicatlán Valley). The conservation status of this species was evaluated by Anguiano-Constante et al. (2018) and found to be Least Concern (LC).

Discussion.

Lycianthes peduncularis is recognized by its combination of prostrate to decumbent habit, simple, ascending-appressed trichomes, small calyces, and round, green fruit with maroon to black striations. The fruits have yellow sclerotic granules in the mesocarp. This species may once have had a broader and more continuous distribution on limestone soils. It is currently restricted to limestone soils on either side of the transvolcanic belt and to some eroded volcanic areas within the transvolcanic belt (rarely on rhyolite) ( Rzedowski 1986). In addition, this species may tolerate other, more unusual, substrates. In Oaxaca, L. peduncularis has been collected near onyx and marble quarries. Several other localities are in or near mining areas. Some of the populations in Oaxaca are atypical in the size and shape of their leaves, the long length of the longest stamen filament, and the straight style ( Dean 2004).

This species was widely cultivated in German botanical gardens in the 19th and early 20th centuries, and an interesting article was written by the German botanist Purpus on how to cultivate the species ( Purpus 1923). Currently, the type of Solanum pedunculare is a neotype at W from the Leipzig Botanical Garden designated by Dean (2004). In his monograph of Lycianthes , Bitter (1919) mentioned that the type material that he studied of S. pedunculare were mixed collections representing both L. moziniana and L. peduncularis ( Bitter 1919). As previously detailed in Dean (2004), Schlechtendal cites three syntypes. One is based on cultivated material from the Halle Botanical Garden (which he indicates is of primary importance, because he cites it after the species epithet as H. Hal) and two herbarium specimens from B, cited near the end of the protologue: Ehrenberg 81 from Hidalgo, Mexico; Schiede s.n. from Michoacan, Mexico.

At the time Dean published the neotypification for S. pedunculare , no authentic material seen by Schlechtendal was available. Recently, the Ehrenberg specimen seen by Schlechtendal has been located at HAL and seen by the first author, and the specimen matches L. moziniana var. moziniana . This specimen is annotated by Schlechtendal as " S. pedunculare , S. mocinianum ?" This indicates that he was uncertain that the specimen was S. pedunculare . The specimen is also annotated by Bitter as L. mociniana , indicating that this is the syntype he saw. The entire Solanaceae collections at GOET, HAL, M, and W were searched in 2019, and no other material of Solanum pedunculare seen by Schlechtendal was located. However, the original material from the Halle Botanical Garden existed at the time Bitter (1919) completed his monograph, and he was clear that that the Halle Botanical Garden material belonged to a different taxon than S. moziniana and matched other material that he annotated as L. peduncularis ; the specimens and material he examined may have been lost in the destruction of the Berlin herbarium during World War II ( Hiepko 1978, 1987; Vorontsova and Knapp 2010).

Because Schlechtendal placed primary importance on the horticultural syntype from the Halle Botanical Garden, we assume that he took his description from that material, material that was shared with other botanical gardens, such as the Leipzig Botanical Garden from which the neotype was collected. The characters in the protologue description of S. pedunculare do not match the Ehrenberg specimen in several important ways. First, the protologue says that S. pedunculare is a branching, prostrate plant, while the Ehrenberg specimen is clearly erect and not highly branched. Second, the protologue describes the root as thick, whereas only narrow underground stems (which lead to a root far beneath the soil surface) are visible on the Ehrenberg specimen. Third, the protologue mentions rhombic-shaped leaves with cuneate bases which are not present on the Ehrenberg specimens. In addition, although the protologue does not mention the density of pubescence, Schlechtendal adds a comment at the end of the protologue that says that the plants in their natural habitat have denser pubescence. By this comment, Schlechtendal acknowledges that the pubescence of the syntypes from Mexico do not match that of the horticultural material from the Halle Botanical Garden. Lycianthes peduncularis as recognized by Bitter (1919), by Dean (2004), and in this treatment is a prostrate, highly branched plant with a very thick root that is very close to the soil surface, rhombic to widely oblanceolate leaves with cuneate bases, and short, sometimes sparse trichomes. In the future, if more authentic material seen by Schlechtendal becomes available, the name S. pedunculare may need to be retypified, however we are not doing so at this time.

Representative specimens examined.

Mexico. Guanajuato: Mpio. San José Iturbide, near Rancho El Guajolote, SW of San José Iturbide, one hwy exit S of exit to San José, dirt rd that goes W to large drainage, farm of Margarita Vargaz Fuentes de Acosta, [20.9019, -100.4215], 6000 ft, 31 Oct 1991, E. Dean 308 (DAV). Hidalgo: cañada de Arrollo Hondo, 25.9 km al noreste de Ixmiquilpan, carretera a Tolatongo, 20.6320, -99.0268, 1870 m, 17 Jun 2000, R. Cruz-Durán 4674 (MEXU). México: N of Huehuetoca along the road to Apaxco, ca. 4.2 road mi from building Los Arcos in dowtown Huehuetoca, E side of rd, near where RR tracks come close to rd, [19.8896, -99.2083], 2134 m, 3 Aug 1991, E. Dean 244 (DAV, MEXU). Oaxaca: Mpio. Mitla, La Colorada, 16.9261, -96.3950, 1767 m, 2 Jun 2009, H. Hernández O. 137 (DAV). Puebla: Mpio. Zapotitlán de las Salinas, San Antonio Texcala, along hwy 125 S of Tehuacán, canyon with onyx mine just N of town, [18.4004, -97.4465], 1677 m, 22 Oct 1991, E. Dean 298 (DAV). Querétaro: alrededores de Bernal, [20.7423, -99.9567], 2200 m, 5 Jun 1992, R. Hernández-Magaña 9905 (MEXU).

Figures

Figure 78. Image of herbarium specimen of L. peduncularis, Dean 226 (DAV). Image used with permission of the UC Davis Center for Plant Diversity.

Figure 79. Map of geographic distribution of L. peduncularis based on herbarium specimen data.