Tradescantia crassula Link & Otto, Icon. Pl. Rar. 2: 13, pl. 7. 1828.

Pellegrini, Marco O. O., Forzza, Rafaela C. & Sakuragui, Cassia M., 2017, Novelties in Brazilian Tradescantia L. (Commelinaceae), PhytoKeys 80, pp. 1-31 : 3

Tradescantia crassula Link & Otto, Icon. Pl. Rar. 2: 13, pl. 7. 1828. Figs 1 , 8

Tropitria crassula (Link & Otto) Raf., Fl. Tell. 3: 68. 1837. Lectotype (designated here). BRAZIL. Rio Grande do Sul: Rio Pardo, fl., fr., s.dat., F. Sellow 3033 (B barcode B100521014!).

Tradescantia crassipes Graham, Edinburgh New Philos. J. Jan.-March: 388. 1829, nom. nud.

Tradescantia schwirkowskiana Funez et al., Phytotaxa 272 (1): 64. 2016. Holotype. BRAZIL. Santa Catarina: São Bento do Sul, borda da ferrovia às margens do Rio Banhados, fl., fr., 16 Nov 2015, L.A. Funez & P. Schwirkowski 5037 (FURB No. 50791!; isotypes: C n.v., HURB n.v.). Syn. nov.

Diagnosis.

Herbs with a definite base, terrestrial, rupicolous or epiphytes. Roots thin, fibrous, cream to light brown, emerging from the basalmost nodes. Stems erect, succulent, rarely to densely branched at the base, sometimes branching at the upper half; internodes medium to dark green, glabrous, sometimes with a leaf-opposed longitudinal line of short, uniseriate, light brown to hyaline hairs in the terminal portion of the stems. Leaves distichously or spirally-alternate, sessile; sheaths light green, sometimes with green striations, glabrous, margin ciliate to setose, hairs hyaline; blades elliptic to broadly elliptic to ovate to broadly ovate to obovate, rarely lanceolate, falcate to complicate, succulent, glabrous on both sides, adaxially glossy light to medium to dark green, sometimes glaucous, abaxially light to medium green, turning olive-green to greyish green to brown when dry, obtuse to truncate, rarely cuneate, margin green, minutely ciliolate to ciliate, slightly revolute, apex acute to obtuse, rarely acuminate; midvein conspicuous to inconspicuous, adaxially impressed to inconspicuous, secondary veins inconspicuous on both sides, sometimes slightly conspicuous on both sides. Synflorescences terminal or axillar in the distal portion of the stems, composed of a solitary main florescence, 1 per leaf axis. Inflorescences (main florescences) consisting of a pedunculate double-cincinni fused back to back; peduncles green, glabrous, sometimes with a leaf-opposed longitudinal line of short, uniseriate, light brown to hyaline hairs; peduncle bracts absent; supernumerary bracts absent; cincinni bracts similar to each other, rarely unequal or reduced in some axillary inflorescences, broadly ovate to ovate, leaf-like, glabrous, adaxially light to medium to dark green, abaxially light to medium green, base cordate to obtuse, not saccate, margin entire to minutely ciliolate to sparsely setose near the base, apex acute; double-cincinni 8-28-flowered. Flowers bisexual, actinomorphic, flat (not forming a floral tube); floral buds broadly ovoid; pedicels green to vinaceous, glabrous, rarely sparsely glandular-pubescent; sepals 3, equal, free, ovate, cucullate, margin hyaline, apex acute, persistent in fruit, dorsally keeled, green, rarely vinaceous, setose, with long hyaline hairs along the keel; petals 3, equal, free, elliptic to ovate, rarely broadly ovate, not clawed (sessile), flat, white; stamens 6, arranged in two series, equal, filaments free from the petals and from each other, filaments straight at anthesis and post-anthesis, basally densely bearded with moniliform hairs, hairs as long as the stamens, white, anthers basifixed, rimose, connective expanded, rhomboid, yellow, anther sacs ellipsoid, divergent, yellow, pollen yellow; ovary sessile, subglobose to globose, white, smooth, glabrous, 3-loculate, locules equal, locule 2-ovulate, ovules uniseriate, style straight, white, cylindrical, conical at the apex, stigma punctate, pistil longer than the stamens. Capsules subglobose, light to medium brown when mature, smooth, glabrous, loculicidal, 3-valved, sometimes apiculate due to persistent style base. Seeds exarillate, 1-2 per locule, ellipsoid to narrowly trigonal, cleft towards the embryotega, ventrally flattened, testa grey to greyish brown, farinose, costate arranged in ridges radiating from the embryotega; embryotega dorsal, relatively inconspicuous, generally covered by a cream farina, without a prominent apicule; hilum linear, longer than ½ the length of the seed.

Specimens seen.

ARGENTINA. Misiones: Cainguás, pequeño campo a la entrada del Salto Golondrina, sobre Arroyo Guiray, fl., fr., 8 Nov 2000, M.E. Múlgura de Romero et al. 2470 (CTES, SI); General Manuel Belgrano, ruta nacional 101, 8 km de Bernardo de Irigoyen hacia San Antonio, Salto Andrecito, fl., 15 Oct 1996, O. Morrone et al. 1393 (CTES, SI). BRAZIL. Minas Gerais: Extrema, trilha para a Pedra das Flores, fl., 24 Oct 2009, G.H. Shimizu 226 (RB, UEC). Rio Grande do Sul: Barão, sudoeste de Garibaldi, Estrada para Carlos Barbosa, fl., fr., 22 Nov 2005, M.C. Machado & L.Y.S Aona 607 (UEC, HUEFS). Santa Catarina: Campo Belo do Sul, Fazenda Gateados, fr., 15 Jul 2008, M. Verdi et al. 2028 (FURB, RB); São Bento do Sul, Floresta Ombrófila Mista, fl., fr., 31 Dec 2013, P. Schwirkowski 197 (FURB). São Paulo: Jundiaí, Serra do Japi, fl., fr., 25 May 1994, J. Semir et al. 31648 (UEC); loc. cit., Trilha do Mirante, fl., fr., 18 Jul 1995, R. Mello-Silva et al. 1074 (SPF); loc. cit., Serra do Jundiaí, sentido bairro Eloy Chaves, próximo à represa do DAE, fl., 23 Jan 1998, E.R. Pansarin 136 (SP, UEC); Itararé, Fazenda Ibiti (Ripasa), beira da estrada Itararé-Bonsucesso, fl., fr., 30 Oct 1993, V.C. Souza et al. 4531 (ESA, RB); São Paulo, Cidade Jardim, fl., fr., 11 Mar 1932, W. Hoehne s.n. (IPA 69219, SPF 17149).

Distribution and habitat.

Tradescantia crassula occurs in Argentina and Brazil (in the states of Minas Gerais, São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul) (Fig. 8 ). It is commonly found growing in rocky outcrops, grasslands and open areas, under full sunlight, as rupicolous or terrestrial. It is also found on roadsides and within the understory of open forests, as terrestrial or, more rarely, as an epiphyte.

Conservation status.

Tradescantia crassula possesses a wide EOO (ca. 408,686.868 km2). Thus, following the IUCN recommendations ( IUCN 2001), it should be considered Least Concern (LC).

Nomenclatural notes.

Funez et al. (2016) indicate that Pellegrini (2015) erroneously designated the specimen Sellow 3033 (B100521014) as the lectotype for T. crassula . However, their affirmation is incorrect according to the Code since the thesis lacks either a ISSN or an ISBN, and was never distributed to the general public ( McNeill et al. 2012, Art. 29.1). The work cited by Funez et al. (2016) was a draft version of the first author’s unpublished M.Sc. thesis, with many incomplete and partially incorrect data (Pellegrini, unpublished data), and therefore is not considered a effective publication by the Code. Furthermore, according to Art. 30.8 ( McNeill et al. 2012), any thesis published on or after 1 January 1953 and stated to be submitted to a university for the purpose of obtaining a degree, does not constitute effective publication; unless it contains any kind of statement or other internal evidence that it is regarded as an effective publication by its author or publisher. Since no statement is made in the final version of the thesis (i.e. Pellegrini 2015), the publication does not meet any of the Code 's requirements, and therefore cannot be treated as effectively published. In the final version, Pellegrini (2015) gives detailed information on the typification of T. crassula , which is effectively published here and corrects the typifications by Funez et al. (2016).

The date written on the original label, and treated by Funez et al. (2016) as the collections date, is "Dec. 1836". Also, it is possible to see in the label the names of Sellow and Humboldt. According to Stafleu and Cowan (1985), Friedrich Sellow lived from 1789-1831, and collected plant specimens in Southern Brazil and Uruguay 1819-1831, funded by Humboldt. This easily explains why both botanists are mentioned in the original label, and why the collector is to be considered as Sellow, instead of Humboldt or both botanists. Furthermore, given that Sellow died in 1831 and his expeditions were done just before his death, it would be impossible for "Dec. 1836" to represent the actual collection date. We believe this date might correspond to the date when this specimen was acquired by Kunth, and placed into his personal herbarium. Finally, Link and Otto (1828) make direct reference to their new species being based on Sellow collections. According to the Code ( McNeill et al. 2012, Art. 9.2), the Sellow 3033 (B100521014) specimen is a suitable choice for a lectotype, superseding the lectotypification of the original illustration, done by Funez et al. (2016). The epitypification by Funez et al. (2016) should be disregarded entirely because the original illustration is informative enough to correctly apply the name T. crassula . All the diagnostic features of this species (see comments below) are visible and sufficient for appropriate diagnosis, in the original illustration.

Taxonomic notes.

The species in this section are especially variable morphologically and when in cultivation or growing in shaded areas they can change their vegetative morphology quite drastically. Few characters in the vegetative organs were observed to be constant in the T. crassula group and thus are of little taxonomic relevance. This can be exemplified by the phyllotaxy and pubescence of the leaf-blades, which have been shown to vary greatly due to ecological features ( Pellegrini 2015, 2016). On the other hand, the pubescence of the internodes, leaf-sheaths, and of the margin of the leaf-blades were observed to be constant and reliable for species delimitation. As previously indicated in other Tradescantia sections ( Anderson and Woodson 1935), the pubescence of the pedicels and sepals seem to be highly stable within each species, easily observable, and thus, reliable for species delimitation. As aforementioned, T. crassula is highly variable in vegetative morphology. All studied individuals always presented glabrous leaf-blades, setose sepals with long hairs along the keel, and white petals. The specimens cited by Funez et al. (2016) as representing T. schwirkowskiana , fit perfectly the circumscription adopted by us for T. crassula , showing variation only in the degree of branching of the stems, color of the leaf-blades, and degree of impression of the secondary veins. All of this morphological variation can be easily explained by the ecological features of the area where the specimens were collected (i.e. shaded moist forests in mountainous regions from the state of Santa Catarina). Aside from that, the authors state that T. crassula possesses spirally-alternate leaves and a rhizomatous base. While developing our studies for the taxonomic revision of T. sect. Austrotradescantia and a morphological phylogeny for the genus ( Pellegrini 2015), we analyzed 50% of the species in the genus and observed that all species of Tradescantia produce spirally-alternate leaves when young. This feature is normally lost during development of most species of T. sect. Austrotradescantia , but is always retained by T. valida G. Brückn. (see comments below), sometimes retained by T. cerinthoides Kunth ( Pellegrini 2015, 2016), and rarely retained by T. crassula (Pellegrini, pers. obs.). No species in Tradescantia were observed to produce rhizomes ( Pellegrini 2015). The only known drought resistance strategy observed in the genus was the production of tuberous roots; present in all species of T. sect. Mandonia , T. sect. Parasetcreasea , T. sect. Separotheca , T. sect. Setcreasea and sect. Tradescantia , and exclusively in T. commelinoides Schult. & Schult.f. from T. sect. Cymbispatha ( Pellegrini 2015). Thus, T. schwirkowskiana is here synonymized under T. crassula .

Figures

Figure 1. Tradescantia crassula Link & Otto. A habit, showing the erect stems, and distichously-alternate leaves with conduplicate blades B detail of the stem and leaf-sheath C detail of the abaxial side of the leaf-blade, showing the lack of hairs and the slightly conspicuous secondary veins D detail of floral buds, showing the setose hairs, restricted to the keels of the sepals E flower F detail of the inflorescence, showing the non-saccate cincinni bracts. Photographs by M. O. O. Pellegrini.

Figure 8. Distribution map of studied Tradescantia L. in the South American domains. Full squares - T. crassula; White squares - T. chrysophylla; Triangles - T. valida; Circles - T. ambigua; Stars - T. boliviana. Light green- Amazon Forest; Orange- Cerrado; Red- Caatinga; Yellow- Chaco and Pantanal; Olive-green- Pampa; Dark green- Atlantic Forest; Purple- Andean Yungas.