Utricularia sect. Foliosa Kamieński

Baleeiro, Paulo C., Gonella, Paulo M., Sano, Paulo T. & Jobson, Richard W., 2022, Unveiling Utricularia amethystina’s true colours: a taxonomic revision of one of the largest species complexes (U. sect. Foliosa, Lentibulariaceae), Phytotaxa 576 (1), pp. 29-54 : 31-33

Utricularia sect. Foliosa Kamieński , Lentibulariaceae preprint from Nat. Pflanzenfam. 120 (1891)

TYPE: Utricularia amethystina Salzm. ex A.St. -Hil. & Girard. (Designated by P. Taylor).

Illustrations: figs.77a,b; 78; 79 P. Taylor (1989); fig.2 Baleeiro et al. 2016, fig.1 Baleeiro et al. 2019.

Description. Terrestrial, affixed sub-aquatic or lithophitic herbs. Rhizoids few to many, simple or ramified branches, normally present semi-aquatic species; stolons few to many, filiform. Leaves simple at peduncle base, or rosulate, lamina filiform, spathulate to circular, base attenuate, apex rounded, ascendant or prostate, 1- or multinerve (0–)1– 7; traps globular, stalk basally inserted c. 1 mm long, two dorsal deltoid appendages with trichomes on abaxially portion and around trap door, chin-like swelling at base of trap present or absent. Inflorescence simple or ramified, erect, glabrous or papillose near base; scales, bract and bracteoles basifix, entire, glabrous; bract deltoid to broadly ovate; bracteoles linear to ovate, united at some degree with the bract; calyx lobes similar or unequal, glabrous, papillose, or with simple or glandular trichomes, margin entire; corolla bilabiate with spur, lower lip violet with yellow surrounded by white spot at base of, or entirely yellow, or white with yellow spot at base; upper lip ovate, elliptic or circular, glabrous or papillose, or simple or glandular trichomes; lower lip obovate to transversally elliptical, base with a prominent bilobed swelling, apex ± entire to deeply 3-lobed. Filament curved to ± straight, theca distinct or subdistinct; polen oblade to prolate, 6–15 colporate. Ovary globose, glabrous or glandular, style usually shorter than the ovary, stigma bilabiate, lower lip semicircular with ciliate margin, upper lip reduced. Capsule globose 1.5–4mm diam., dorsiventrally bivalvate. Seed ovoid to narrowly cylindrical.

Distribution and ecology across the biodiverse regions Cerrado and The Guiana Shield: Utricularia sect. Foliosa is found in most of the countries in South and Central America, Mexico and possibly USA ( Fig.1 ); however, it is in the Brazilian Cerrado (including campos rupestres) and the Guiana Shield formation the responsibility for the striking diversity not only inside this section, but also for the entire genus Utricularia ( Taylor 1989) . These adjacent complex regions have been documented highly important due to their high levels of diversity and endemisms of vascular plants ( Giulietti et al. 1997; Kelloff & Funk 2004; Funk et al. 2007). U. sect. Foliosa habitat elevation ranges from sea level in the Brazilian restingas to 2994 m on Neblina peak in Brazil and countless table mountains in the pantepui province (e.g. Mt. Roraima and Kukenan tepui ~ 2800 m). Even though a range of different elevation is seen with one of the newest species from Pantanal wetlands shown in this study, the greatest levels of diversity and endemism seem to be associated with high elevations and cooler climates in three main areas, such as the campos rupestres of the quartzitic massifs of the Chapada dos Veadeiros ( Souza & Bove 2012) and Espinhaço Range in Brazil and the pantepui province of the Guiana Shield. These regions have been traditionally reported as showing similar levels of richness and distribution for other group of plants ( Rapini et al. 2008; Rando & Pirani 2011).

The “archipelago” nature provided by the pantepui province with tabletop mountains above the surrounding rainforest is a unique biogeographic region and harbours an incredible diversity. The evolutionary historic pathways provided by these so called “islands in the sky” across the landscape is still controvertial, but nonetheless, their old uplifting age has probably been providing as a barrier and limiting genetic flow, in the flora of the different tabletop Mountains. The Pantepui is less than one percent in area of the total Guiana Shield. Yet, it harbours about 2450 vascular plant species, with 60% endemic to the Guiana Shield, 40% to the Pantepui and 25% to a single mountain ( Berry & Riina 2005). According to the same authors, the genus Utricularia comes in the list of the richest genera for the Pantepui flora (21spp.), but we think this number is underestimated as new species of animals ( Kok, 2010; Kok et al., 2015, 2018) and not as much of plants ( Barbosa-Silva et al., 2018) have been introduced.

The study of Vasconcelos et al. (2020) shows recent and rapid radiations (around 2–5 Myr) of different linneages on an ancient formation of campos rupestres in Brazil. It points out studies of plant radiations in such old mountains, unlike what is more recently seen in the literature of lineage age matching mountain uplifting. Another study show recent radiations (2–4 Myr) rather than old of the endemic lineages of frogs Tepuihyla (of the 7 spp., 4 ssp. are known from a single tepui) in an ancient region this time the pantepui province presented by Salerno et al. (2012).

Notes: Examination of all binomials and morphotypes of U. sect. Foliosa using morphometric analyses (descriptive and multivariate) ( Baleeiro et al. 2016) and molecular phylogenetics ( Baleeiro et al. 2019) highlighted the need to reassess 11 synonymised taxa. Seven of these were considered accepted species prior to Taylor`s taxonomic treatment of the genus and are here raised to species level ( Taylor 1989). A further three non-synonymised taxa included in the study are here described as new species.

Characters that group the taxa in the section include the basally positioned trap door with two trichome-covered dorsal appendages, bract and bracteoles basifix, bracteoles usually attached near the base or up as high as the middle length of the bract, and capsule dehiscence via a dorsiventral slit. Key defining characters between species include the shape and size of corolla lower and upper lip, calyx, and corolla colour and indumentum, and the pedicel and peduncle length ( Baleeiro et al. 2016). At the between section level defining characters include the small stature of the stamens that does not differ across the section, although the size of which is not seen across the genus. Pollen size and shape can vary strongly between species, but also within the same population or on an individual. Therefore, these two latter characters are not considered useful for differentiation at the specific level. In addition, a morphometric study of seed size and shape across and between U. sect. Foliosa and U. sect. Psyllosperma ( Menezes et al., 2014) shows that there is insufficient morphological information for differentiation at the specific level and sectional levels.

Figures

FIGURE 1. Geographic distribution map of Utricularia sect. Foliosa species. A. Distribution of all 14 species in South and Central Americas. B. Map of the species distribution in the Espinhaco range and Chapada dos Veadeiros National park. C. Map of the species distribution at the Guiana Shield.