Drosera communis Saint-Hilaire [1824

Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, Phytotaxa 553 (1), pp. 1-76 : 32-35

10. Drosera communis Saint-Hilaire [1824 : t. XV(1)]. Figures 4d, 12a–d

Lectotype (designated by Correa & Silva 2005):— BRAZIL. São Paulo: “Mogy das Cruses” [Mogi das Cruzes], s.d., Saint-Hilaire D-722bis (P-00631824!).

= Drosera parvifolia Saint-Hilaire (1826: 263) .

Lectotype (designated here):— BRAZIL. Minas Gerais: São João del Rey, s.d., Saint-Hilaire D-377 (P-00749170!; isolectotype P-00706171!).

= Drosera intermedia var. tenuis Eichler in Martius & Eichler (1872: 392).

Neotype (designated here):— BRAZIL. São Paulo: Morro Pellado [Itirapina], January 1901, Edwall 697 (SP-8970!).

= Drosera montana f. parviflora Chodat (1903: 539) .

Lectotype (designated here):— PARAGUAY. Iter ad “Yerbales” montium “ Sierra de Maracayú ”, November, Hassler 5271 [G-00381738!; isolectotypes BM-590380!, G-00381739!, G-00381746!, K pro-parte!—mounted on the same sheet as Hassler 5634, P-749152!, P-749153!, UC!].

= Drosera communis var. alba Hoehne (1915: 28 , t. 124, f. 3).

Lectotype (designated by Correa & Silva 2005 ):— BRAZIL. Mato Grosso do Sul: Coxim , June 1911, Hoehne 3358 (SP!; isolectotypes R!, US-00642067!).

Perennial, rosetted, acaulescent or forming etiolated stems when growing semi-aquatically. Leaves semi-erect or decumbent, with geniculate-involute vernation, distinctly petiolate, spatulate, petioles narrow, abruptly broadening into the broadly to narrowly obovate to suborbicular lamina, petioles sparsely eglandular pilose on the abaxial surface and glabrous to glabrescent on the adaxial surface; stipules rectangular in outline, divided into several laciniae from the base. Scapes arcuate at the base, often uncinate, base glabrous to very sparsely eglandular-pilose; sepals usually exclusively glandular-pilose, but rarely with sparse eglandular trichomes; petals white to light pink; gynoecium 3- carpelate, styles bifurcated at the base. Seeds fusiform, testa reticulate, pale brown.

Illustrations:— Saint-Hilaire (1824: t. XV—two habitus drawings); Eichler (1872: t. 90, fig. II pro parte: habit illustrated on the left and flower parts 2, 2II, 4—as Drosera intermedia ); Hamet (1907: t. II, fig. 5—seed); Hoehne (1915: t. 124, fig. 3—habit and details, as D. communis var. alba ); Duno de Stefano et al. (2001: 11, fig. 2—habit and details); Rivadavia (2003: 89, figs. 4.2A-E, 4.1F, G—habit and details).

Distribution:— Colombia, Venezuela, Brazil (North: AP, RR, TO; Northeast: BA, PB, PE, RN; Central-West: DF, GO, MS, MT; Southeast: MG, RJ, SP; South: PR, RS, SC; Fig. 4d), Bolivia, Paraguay, and Argentina.

Habitat: —Found in a wide range of habitats and soil types, ranging from very wet (growing partially submerged) to only slightly moist soils, from peat- and sand-based soils to red clay, from growing exposed in full sun to partially shaded sites in forested areas (gallery forests). In the Cerrado and Amazon Rainforest domains it grows in year-round wet areas among sparse to dense grasses in sandy soils of savanna vegetation, such as in the veredas and open riverine habitats. In the Cerrado domain, D. communis is also common in perennially wet areas of campos rupestres vegetation. In the Atlantic Forest domain, it is found in wet grasslands in sandy and clayish soils, often spreading to disturbed areas such as eroded road and trail sides. It also occurs at sea level in restinga vegetation in NE Brazil. Collected between 0–1500 m a.s.l.

Phenology:— Found with flowers year-round.

Conservation status:—Least Concern (LC). Drosera communis is the most widespread and common Drosera species across South America ( Brazil: AOO= 1,224 km 2, EOO= 6,368,836 km 2; global: AOO= 1,448 km 2, EOO= 10,476,860 km 2), found in a wide range of habitats. In Brazil, it is known from several National Parks (Brasília, Chapada dos Guimarães, Chapada dos Veadeiros, Emas, Sempre-Vivas, and Serra do Cipó), State Parks (Biri-Biri, Pirineus, Rio Preto, Serra Nova, Serra do Cabral), and other protected areas.

Notes: — Drosera communis is diagnosed by the acaulescent habit, spatulate leaves with lamina suborbicular or narrowly to broadly obovate, scape base arcuately curved and often hook shaped (uncinate), scape base glabrous to sparsely eglandular-pilose (Fig. 12a, b, d), sepals glandular-pilose, and seeds fusiform. It is most similar to D. viridis , from which it is distinguished by characters discussed under that species and in Rivadavia (2003).

The species was originally described from marshes in São Paulo and Minas Gerais states (Saint-Hilare 1824: t. XV, p. 2). However, this species presents a much wider distributional range, showing some morphological variation across it, mostly in terms of leaf shape (Fig. 12a, b, d; narrowly spatulate with narrowly obovate lamina to spatulate with suborbicular lamina), indumentum (pilose to sub-glabrous) and orientation (decumbent to semi-erect), but also in the pilosity of the scape. Several characteristics, however, were commonly observed varying within populations, such as size, color, shape, indumentum, and orientation of the leaves, as well as flower color (from white to pink; see Fig. 12c), all of which may be mostly associated with habitat gradients, such as water availability and luminosity. Therefore, D. communis is here interpreted as a single very variable and plastic species.

Neither the type specimen of D. intermedia var. tenuis as cited by Eichler (1872) (SÃO PAULO: in humidis ad Batataçs [Batatais] prov. S. Paulo, June, Riedel s.n.) nor any duplicates of the type collection could be located in any of the herbaria visited or contacted, including those where most of Riedel’s collections were sent to (e.g. BM, LE, M, R). However, based on the original description [Eichler (1872: 392, literally translated): “more slender than in the type, leaves somewhat smaller, petioles ciliate-pubescent, scape hair-like, sub-flexuose, few- (2-4)flowered”] and geographic distribution (Batatais, SP) provided by Eichler (1872), this taxon is undoubtedly conspecific with D. communis , being the only species from that area that fits the description. The only other species known to occur in the same geographic region are D. lutescens (easily distinguishable by the densely eglandular-pilose scapes) and D. grantsaui (caulescent, with oblong leaves and scapes with erect base). Since no original material is known, it was necessary to select a neotype to fix the name (ICN Art. 9.8; Turland et al. 2018). We selected a specimen from the same region and fitting the description as the neotype.

Eichler’s (1872) concept of D. intermedia var. americana partially included D. communis , which is clear by the specimens cited for Brazil (e.g., Martius 476) and some of the illustrations in that publication. In Tab. 90, figure II, the habit illustrated on the left and the flower parts (2, 2II, and 4) clearly represent D. communis due to characteristics such as the long scapes with larger flowers and glandular calyx, while the habit illustrated on the right and seed drawings represent D. intermedia (glabrous calyx and ovoid seeds with papillose testa).

Drosera montana f. parviflora was considered a synonym of D. communis by Duno de Stefano et al. (2001) and Rivadavia et al. (2014). The name was described by Chodat (1903) based on the specimen Hassler 5271, from which many duplicates are known from different herbaria. Duno de Stefano et al. (2001) cite a “ holotype ” at G, however, this does not give rise to an inadvertent lectotypification as it was published after January 1 st, 2001 and lacks the words “here designated” (ICN Art. 7.11; Turland et al. 2018). Since three duplicates of this collection are found at G, where Chodat developed his works on the Flora of Paraguay, the specimen G-00381738 is here designated as the lectotype, since it is the most complete among the G specimens.

The type specimens of D. parvifolia represent dwarfed individuals of D. communis ( Rivadavia et al. 2014) . This difference in plant size could be explained by the fact that D. parvifolia was collected growing in clayish soil (herbarium label of Saint-Hilaire D-377) but could also be linked to hydric stress. This taxon has been historically associated with D. montana ( Diels 1906, Correa & Silva 2005 ) probably due to the presence of eglandular trichomes at the base of the scape (a character present in the holotype of D. parvifolia , but not in the isotype). This trait is somewhat common among D. communis (especially in that geographic region) and can even be found in some of the individuals in the species’ syntypes (but not in the lectotype).

Drosera communis is known to form rare natural hybrids with D. hirtella and D. lutescens when sympatric (see ‘Natural Hybrids’ below for specimens examined and photographs). Hybrids present intermediate leaf shape and orientation, as well as conspicuous eglandular trichomes on scapes colored similarly to those of the respective parent species: red ( D. hirtella ) or white ( D. lutescens ). These hybrids are found only as scattered individuals among the parent species’ populations and it is unknown whether they are fertile. Introgression with D. lutescens may explain eglandular trichomes on the scapes of some D. communis populations (including D. parvifolia ) in areas where the ranges of both species overlap.

The record from Argentina is based on Dawson (1938), which registers D. communis var. pauciflora Eichler in Martius & Eichler (1872: 394) to the country, a name that is here considered synonymous with D. montana . Examination of the specimen cited in that work [L. Hauman I (BA-34678)], however, verified it is D. communis instead, confirming the occurrence of the species in Argentina.

Representative specimens examined: — BRAZIL. Amapá: Porto Grande , 15August 2017, Laste 24 ( UEC) . Bahia: Abaíra, Catolés , 26 July 1995, Rivadavia-Lopes 478 ( SPF) . Camaçari, estrada Salvador-Camaçari-Dias D’Ávila. 14 August 2003, Rivadavia 1690 ( SPF) . Distrito Federal : Planaltina, Estação Ecológica de Águas Emendadas , 20 February 2009, Meneguzzo & Somavilla 122 ( UB) . Goiás: Chapada dos Veadeiros, 14 February 1966, Irwin et al. 12792 (NY, UB) . Mato Grosso: Nova Xavantina, Fazenda Brasil , 28 March 1997, Árbocz et al. 3711 ( ESA, UFMT) . Mato Grosso do Sul: Costa Rica , estrada para Alcinópolis, 28 October 2001, Rivadavia-Lopes 1304 ( SPF) . Minas Gerais: “Marais pres Capueirinha”, Saint-Hilaire D-414 (P-00631821!, P-00631823 pro -parte! [mixed with Saint-Hilaire 695], MPU-011030 image!—original material). “Marais pres S. Miguel de Mato Dentro ”, Saint-Hilaire B1-695 (P-00631822!, P-00635417!—original material). “Marais dans le prov. de Minas et de St. Paul”, Saint-Hilaire s.n. (B-10 0272050!, K-000432545!—original material). Moeda , Serra da Moeda , 08 March 2007, Batista 1988 ( BHCB) . Prata , ao longo da BR-153, 04 March 2006, Rivadavia & Demets 2154 ( SPF) . Santa Rita de Jacutinga , cachoeira às margens da BR-494, 26 December 2009, Gonella et al. 251 ( SPF) . Paraíba: Km 78 estr. Recife-João Pessoa, 30 June 1967, Lima 67-5049 ( IPA) . Paraná: Ponta Grossa , 26 December 1984, Krieger 20043 ( CESJ, SPF) . Pernambuco: Goiana , January 1988, Pereira s.n. (IPA-49830) . RIO DE JANEIRO: Nova Friburgo, início da estrada para Macaé de Cima , 20 January 2007, Rivadavia et al. 2465 ( SPF) . Rio Grande do Norte: Rio do Fogo, Lagoa da Cotia , 11 October 2015, Garcia & Gonçalves 52 ( UFRN) . Rio Grande do Sul: Caxias do Sul, Fazenda Pedro Hoffmann , 15 December 2012, Grizzon 119 ( FLOR, HUCS) . Roraima: Pacaraima , BR-174, 26 May 2007, Rivadavia 2573 ( SPF) . Rio Branco, Surumu , September 1909, Ule 8392 (G, K) . São Paulo: São Paulo, Parelheiros , 11 February 2006, Rivadavia & Miranda 2145 ( SPF) ; in paludosis ad S.Paulo, December, Martius 476 (M). Santa Catarina: Alfredo Wagner , km 111 da rodovia BR-282, 27 April 2007, Rivadavia 2505 ( SPF) . Tocantins: Mateiros, margem esquerda do Rio Novo , 08 May 2001, Proença et al. 2521 ( UB) .