Drosera cayennensis Sagot ex Diels (1906: 86)

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 : 28-31

7. Drosera cayennensis Sagot ex Diels (1906: 86) . Figures 4c, 11a–c

Lectotype: — FRENCH GUIANA. Bei Cayenne in der Savana [only on the B specimen, the P and K specimens just denote “Cayenne”], 1859, (Herb. Sagot No 1228) Leprieur s.n. [ P-749150 ! first-step lectotype designated by Duno de Stefano & Culham (1995), secondstep lectotype designated here ; isolectotypes B-6813!, K-000432533!, P-749149 !].

= Drosera sanariapoana Steyermark (1952: 243) .

Type: — VENEZUELA. Amazonas: wet savanna, vicinity of Sanariapo, near Río Sanariapo, tributary of Orinoco , 08 September 1944, Steyermark 58472 (holotype F-0055165!; isotypes NY-00328844!, VEN-31269 image!) .

= Drosera colombiana Fernández (1965: 226) .

Type: — COLOMBIA. Meta: Llanos de San Martín , en sabana, July 1948, Dryander 3019 (holotype US-1933748!; isotype COL-100577 fragm. image!) .

= Drosera panamensis Correa & Taylor (1976: 390) .

Type: — PANAMA. Veraguas: La Yegunda, Altos de Baltazar y el Veladero, 650 m, 04 August 1976, Correa et al. 2215 (holotype PMA-54042 image!; isotypes CHR, COL-000001433 image!, DUKE-10000516 image!, F-0055160!, K-000432557!, MEXU-00206621 image!, MO-176758!, NSW, U-0001634 image!, US-00100651!) .

= Drosera pumila Santos (1986: 305 , as “ pumilla ”).

Type: — BRAZIL. Mato Grosso: Cataqui-Iamain, Campo dos Urupás, December 1918, Kuhlmann 1987 (holotype R-000027694!) .

Seasonal geophyte perennial, rosetted, acaulescent. Leaves decumbent, with geniculate-involute vernation, distinctly petiolate, spatulate, lamina obovate to obovate-cuneate; stipule rectangular in outline, divided into laciniate segments from near the base. Scape erect at the base, short, 2.5–8.0 cm long, 1–4(–8)-flowered, densely to sparsely eglandularpilose from base to apex, occasionally also sparsely glandular-pilose towards the apex; sepals lanceolate, united at the very base, exclusively eglandular-pilose, or both glandular- and eglandular-pilose, the glandular trichomes shorter and sparser than the eglandular, reflexed in the fruit; petals light pink to white; gynoecium 3-carpelate, styles bifurcated at the base. Seeds ovoid, testa foveolate.

Illustrations: —Duno de Stefano (1995: 81, figs. 1h–m—habit and details); Silva & Giulietti (1997: 97, figs. 11J–S— habit and details).

Distribution: —Central America: Costa Rica, Panama; South America: Colombia, Venezuela, Guyana, Suriname, French Guiana, Peru, Brazil (North: AC, AM, AP, PA, RO, RR, TO; Central-West: DF, GO, MT; Fig. 4c), and Bolivia.

The distribution here presented for D. cayennensis in Brazil is much broader than previously reported for this species, which was so far only recorded from the states of Amazonas, Pará and Rondônia ( Correa & Silva 2005 , Silva 2010 ). It is also first reported for Costa Rica.

Habitat: —Sandy and clayish soils in seasonally wet areas of savanna in the Cerrado and Amazon Rainforest domains, and also in campo rupestre vegetation in sandy-clayish soils with quartz gravel. Found from sea level to 1600 m a.s.l.

Phenology:— In Brazil, D. cayennensis has been found with flowers between December and March, which corresponds to the wet season. The species survives underground as dormant roots during the dry season, usually from April to September, when its presence is completely imperceptible.

Conservation status: —Least Concern (LC). Drosera cayennensis is a widespread species found in large populations across its range ( Brazil: AOO= 92 km 2, EOO= 3,826,685 km 2; global: AOO= 256 km 2, EOO= 7,484,077 km 2). The species is, however, threatened by the expansion of agriculture and habitat transformation for cattle ranching. In Brazil, it occurs inside protected areas in the National Parks of the Campos Amazônicos (AM, RO), Chapada dos Guimarães (MT), Chapada dos Veadeiros (GO) and Viruá (RR), as well as in the State Park of Xingu (MT) and the State Forest of Trombetas (PA).

Notes: — Drosera cayennensis presents a vegetative morphology very similar to that of D. hirtella Saint-Hilaire (1826: 262) and D. lutescens ( Saint-Hilaire 1826: 263) Gonella, Rivadavia & A.Fleischm. , but is easily distinguished from those species by the shorter scapes up to 8 cm long (vs. longer scapes usually longer than 10 cm long), with erect base (Fig. 11b; vs. arcuate base), exclusively eglandular-pilose from base to apex to sometimes also glandular-pilose towards the apex (vs. always both glandular and eglandular-pilose), eglandular trichomes white (vs. red in D. hirtella ), sepals lanceolate and united only at the very base (vs. elliptic and united at basal 1/3), petals light pink to white (Fig. 11c; vs. pink), and seeds with foveolate testa (vs. reticulate).

The species shows a high variability regarding its scape indumentum, from densely and exclusively eglandularpilose to sparsely eglandular-pilose at the base, becoming densely (and sometimes exclusively) glandular-pilose at the apex. Such variability is especially visible in the southern range of this species, in Central-West Brazil (GO, DF, MT). This could perhaps be a result of introgression between this species and D. lutescens and/or D. hirtella . Suspected hybrids between D. cayennensis and D. hirtella have been observed at one site near Cristalina, Goiás, but it is unknown if these hybrids are fertile (see ‘Natural Hybrids’ below for specimens and photograph).

Correa & Silva (2005) placed D. pumila under synonymy of D. montana , however, leaf and sepal morphology, as well as scape indumentum are coherent with the inclusion of this name under D. cayennensis synonymy, as first suggested by Rivadavia (2005) and further supported by the morphological studies of Rivadavia et al. (2014). For the present work, the holotype of D. pumila was thoroughly examined and no difference was observed between this taxon and the exclusively eglandular-pilose morphotype (representing the type) of D. cayennensis . In discordance with Correa & Silva (2005: 48) , who claimed the type material to be missing and probably lost at R (“probablemente esté extraviado”), the holotype of D. pumila was found and personally studied at R by the current authors, making superfluous the lectotypification of the illustration in Santos (1986) by Correa & Silva (2005) . The original spelling “ pumilla ” of the epithet by Santos (1986) is a misspelling of the Latin word “ pumila ” (meaning “dwarf”; correctly spelled in the handwritten label attached to the holotype), therefore it is an orthographic error correctable under ICN Art. 60.1 ( Turland et al. 2018), without the need for conservation of the name.

Contrary to Fernández (1965) and based on the analysis of the type material of both D. colombiana and D. cayennensis , it was here found that these two taxa share the same scape and sepal indumentum and sepal shape, thus, D. colombiana is also considered a synonym of D. cayennensis (as already proposed by Duno de Stefano & Culham 1995).

The record of D. kaieteurensis for the Viruá National Park by Costa et al. (2016) actually represents a misidentified specimen of D. cayennensis .

Diels (1906) cites the specimen “ Sagot 1228 ” as the type, however, this number represents the Sagot’s herbarium genus code, and not a collector’s number. The specimen was actually collected by Leprieur and duplicates are found in different European herbaria, which are by definition syntypes, making a lectotypification necessary. Since Diels (1906) validated a name written by Sagot on the herbarium label (“ msc. in schedis. ”), and the only duplicate with both Sagot’s and Diels’ handwritten labels is the one at B, that would be the natural choice for a lectotype. However, Duno de Stefano & Culham (1995) cite a “type” only for P, which is considered as inadvertent lectotypification (ICN Arts. 7.11 and 9.10; Turland et al. 2018). Since two duplicates of such specimen are found at P, but Duno de Stefano & Culham (1995) mention no unique specimen identifier (such as herbarium inventory number or barcode), we make here a second-step lectotypification (ICN Art. 9.17; Turland et al. 2018) by selecting the specimen with Sagot’s handwritten attached diagnosis (P-749150) as the lectotype.

Representative specimens examined: — BRAZIL. Acre: Cruzeiro do Sul , Estrada Alemanha, 27 May 1971, Fittkau P13311 ( INPA) . Amapá: Coastal Region , between Rios Cujubim and Flechal, 08 August 1962, Pires & Cavalcante 52401 (K, NY). Amazonas: “Estrada do Estanho” road to Igarapé Preto, ca. 60 km SE of Transamazon Highway, 02 July 1979, Calderon et al. 2744 ( US). Canutama, BR-319, savanna a 80 km de Porto Velho, 23 March 2013, Bigio et al. 613 ( RON) . Distrito Federal : Fazenda Água Limpa, divisa com Reserva Ecológica do IBGE, 14 March 2009, Meneguzzo et al. 84 ( UB) . Goiás : Alto Paraíso de Goiás , limite nordeste do Parque Nacional da Chapada dos Veadeiros, 14 April 1995, Rivadavia & Ogassavara 384 ( SPF) . Pirenópolis , lado esquerdo da estrada que sobe a serra para as cachoeiras, 07 January 2001, Rivadavia 1242 ( SPF) . Mato Grosso : Chapada dos Guimarães, nascente ao lado do córrego da Mata Fria , 23 February 1994, Rivadavia & Cardoso 255 ( SPF) . São Felix do Araguaia , próximo à cidade, 28 March 2008, Cardoso 107 ( SPF) . Pará : Óbidos, Floresta Estadual do Trombetas, 07 June 2019, Zappi et al. 4793 ( MG) ; ibid., 09 June 2019, Nunes et al. 548 ( MG) . Vigia , Campina do Palha, 20 January 1950, Black 50- 8639 ( US); ibid., direita da PA-140, 17 March 2001, Rivadavia 1247 ( SPF) . Rondônia : Basin of Rio Madeira , Margin of Mutumparaná airstrip, 25 November 1968, Prance et al. 8860 ( INPA, K, NY, US). Roraima: Boa Vista, lado leste do km 570 da BR-174, 27 May 2007, Rivadavia 2583 ( SPF) . Caracaraí , PARNA Viruá, 23 July 2010, Barbosa 1284 ( INPA, UEC) . Tocantins : Mateiros, APA Jalapão, 11 June 2006, Rivadavia 2192 ( SPF) .

Material outside Brazil examined: — COSTA RICA. San José : Turrubares, Cuenca del Tárcoles, 10 October 2009, Hammel et al. 25428 ( MO) .