Solanum polyphyllum Phil., Anales Museo Nacional, Botanica 2: 64, 1891

Moreira-Munoz, Andres & Munoz-Schick, Melica, 2020, Rediscovery and taxonomic placement of Solanum polyphyllum Phil. (Solanaceae), a narrow endemic from the Chilean Atacama Desert, PhytoKeys 156, pp. 47-54 : 47

Solanum polyphyllum Phil., Anales Museo Nacional, Botanica 2: 64, 1891 Figures 1 , 2

Type.

Chile. Tarapacá Region: prov. Tarapacá, Pachica, 12 Mar 1885, C. Rahmer s.n. (lectotype, designated here: SGO [SGO000004586 acc.#55603]; isolectotypes: B [destroyed, F neg. 2739], CORD [CORD00004258], SGO [SGO000004587 acc.#42779]). Images available via https://plants.jstor.org/.

Description.

Perennial, robust herbaceous plant up to 100 cm tall. Stems thick, glabrescent, internodes with a wing up to 3 mm wide. Leaves simple, the blades 3-4 (-8) cm long x 2-4 cm wide, ovate-lanceolate, sessile, base decurrent on the winged petiole, shiny or with few thick hairs, with yellow crystals included in the midrib and stems; upper leaves shorter and thinner. In the buds, there is an oval leaf, with a petiole that has some whitish hairs. Inflorescence 7-11 cm long, leaf-opposed, with 12-30 flowers; pedicels filiform 10-12 mm long, with few white hairs 0.5 mm long, which continue in the calyx; calyx 4-5 mm long, with a short tube, ¼ -1/3 of its length, divided into five almost linear divisions, 1 mm wide. Corolla blue, ca. 15 mm in diameter, pentagonal, with five shallow divisions, purple colored at its base forming a star, that is alternated with notorious oblong and yellow-green nectaries, pubescent abaxially mainly towards the apices of the divisions, glabrous adaxially. Stamens unequal; anthers differing in size, 4 of 6-9 mm long, 1 shorter of 4-7 mm long, or 3 shorter and 2 longer, tapered, the narrow apex with an elongating pore, the longer anthers curving towards the shorter ones. Style curved and longer than the anthers, stigma capitate. Fruit 5-6 mm in diameter, a glabrous, globose, shiny green-orange berry. Seeds white, ca. 2 mm long, ca.1.5 mm wide, reniform, with a reticulate surface (Fig. 2 ).

Distribution.

Endemic to the Atacama desert of northern Chile; only known from two localities in the precordillera of Tamarugal province, Tarapacá region.

Ecology and habitat.

Solanum polyphyllum grows between loose rocks of an alluvial cone on the north side of the Camiña river. It corresponds to a plant of 100 cm high, erect stems, very blue flowers and green-orange berries. The population is composed of only a dozen exemplars. The vegetation of the site is an open bush of low coverage (15%). Other species present on the site are: Cistanthe amarantoides (Phil.) Carolin ex Hershkovitz ( Montiaceae ), Encelia oblongifolia DC., Helogyne apaloidea Nutt. (both Asteraceae ), Malesherbia tenuifolia D.Don ( Passifloraceae ), Huidobria fruticosa Phil. ( Loasaceae ), Allionia incarnata L. ( Nyctaginaceae ) and Exodeconus integrifolius (Phil.) Axelius ( Solanaceae ).

Conservation status.

The limited representation in herbaria, as well as the low abundance in the field, makes the Solanum polyphyllum a candidate for threatened status. Due to its distribution in the two known locations of Compe and Pachica it is Data Deficient, pending further field work. Solanum polyphyllum potentially could be found in Isluga National Park but new surveys are required to corroborate its presence in this protected area.

Discussion.

In its broadly decurrent leaves on the stem, S. polyphyllum is similar to S. paposanum Phil., which grows both in Perú and in Chile, from 200-3500 m elevation. It differs from S. paposanum in its entire (versus margins with 4-5 acute lobes in S. paposanum ) and glabrous leaves (versus moderately pubescent adaxially and velutinous abaxially in S. paposanum ).

Solanum polyphyllum was described by Rodulfo Amando Philippi based on specimens collected in Pachica (19°51'58"S, 69°25'56" W, 1622 m alt.) by Carlos Rahmer during a journey to Tarapacá made in 1885. Of this gathering, two duplicates are conserved in SGO. We designate as lectotype SGO000004586 (acc.#55603, Fig. 1 ), which is very complete and has the handwritten label of R.A. Philippi. The duplicate specimen (SGO000004587, acc.#42779) has a label written by Federico Philippi (son of R.A. Philippi) who also participated in the 1885 expedition.

The rediscovery of this remarkable plant provides an opportunity to promote more intensive fieldwork in the Tarapacá cordillera, at the transition belt between the desert and precordillera vegetation types, where vegetation greening seems to occur more often due to regional climate change. Despite the sparse vegetation that dominates in the Atacama, new botanical discoveries in different plant families are currently happening, as in Asteraceae [ Senecio ] ( Calvo and Moreira-Muñoz 2019, 2020), Basellaceae [ Anredera ] ( Moreira-Muñoz and Muñoz-Schick 2018), and Solanaceae [ Schizanthus ] ( Morales et al. 2020).

Additional specimens examined.

Chile. Tarapacá Region, Route A-45 towards Camiña, Compe locality, 19°21'9"S, 69°31'18"W, 1950 m alt., 16 May 2019, A. Moreira 3038 (SGO).

Figures

Figure 1. Solanum polyphyllum Phil. (lectotype: C. Rahmer s. n., SGO 000004586 acc. 55603).

Figure 2. Solanum polyphyllum at an alluvial cone at the Tarapaca precordillera A habitat B flower details C leaves D flower E calyx F fruits G seeds H habit. Photos by A. Moreira-Munoz, drawings by M. Munoz-Schick.