Cuphea micrantha Kunth (1824: 196)

Facco, Marlon Garlet & Cavalcanti, Taciana Barbosa, 2023, Taxonomic Revision of Cuphea sect. Trispermum s. l. (Lythraceae), Phytotaxa 588 (1), pp. 1921-1935 : 1921-1935

14. Cuphea micrantha Kunth (1824: 196) .

Lectotype (designated by Duré & Molero 2000: 228):— VENEZUELA. “ Crescit ad ripam Orinoci, prope Santa Barbara [approx. 3.949, -67.076] et juxta San Carlos de Rio Negro ”, May [1800], Humboldt & Bonpland 1119 ( P [00679415] image!, isolectotype B image!) . Figs. 12I–N , 23 .

Cuphea euphorbioides Saint-Hilaire (1833: 112) . Lectotype (here designated):— BRAZIL. Minas Gerais: “Lecta prope pagum Contendas [ Brasília de Minas , approx. -16.215, -44.438] parte desertâ occidentalique provinciae Minas Geraes vulgò Sert ã o”, [1817], Duarte 104 (P [01901735] image!, isolectotype P [01901736] image!).

Cuphea hirta De Candolle (1828: 86) . Lythrum domingense Sprengel ex De Candolle (1828: 86) . Melanium hirtum Sprengel (1825: 454) . Type:—[ DOMINICAN REPUBLIC]. “St. Domingo”, Bertero s.n. (holotype M [0146341] image!).

Cuphea micrantha var. longeciliata Lourteig (1987: 9) . Type:— BRAZIL. Minas Gerais: mun. Prata, about 30 km S of the crossroads Uberlândia-Ituiutaba , open woodland on sandy soil [approx. -19.547, -48.828], 20 January 1978, Pedersen 12087 (holotype P [01901737] image!, isotypes C image!, CTES image!, P [01901738] image!), syn. nov.

Cuphea rapunculoides Grisebach (1866: 105) . Lectotype (designated by Graham 2005: 300):— CUBA. “Cuba occ.” [Pinar del Río], 1863, Wright 2538 (#330) (GOET [005522] image!, isolectotypes BM image!, F, GH, HAC, K image!, MO image!, US, YU image!).

Cuphea valerii Standley & Williams (1952: 125) . Type:— HONDURAS. Departamento El Paraíso, dry rocky hills about 5 kms East of Ojo de Agua [approx. 14.059, -86.871], alt. 760 m, 4 September 1946, Williams & Molina R. 10486 (holotype US [00117349] image!, isotype BM image!, GH image!, US [00997654] image!).

Subshrubs 10–40 cm tall; stems erect, indumentum hirsute and pubescent, long glandular trichomes, ca. 1 mm long, eglandular trichomes <0.5 mm long, with curved apices; internodes 0.8–2 cm long; brachyblasts absent. Leaves opposite, membranaceous, sessile to petiolate, petioles 1–1.5 mm long, blades 8–65 × 4–15 mm, narrow-ovate, ovate, oblong to elliptic, apex acute, base attenuate to obtuse, rarely subcordate, margin plane, indumentum strigose on both surfaces, mixed with sparse glandular trichomes; brochidodromous. Racemes 5–20 cm long, bracteose to frondosebracteose, simple to compound, elongated; bracts 1.5–30 × 0.8–11 mm, subequal pairs, similar to leaves in shape and indument. Flowers alternate; pedicels 1–2 mm long; bracteoles ca. 0.3 mm long, suborbicular; floral tubes 4–6 mm long; spur acute to obtuse, horizontal to deflexed; outer surface purple on the dorsal region, green ventrally, glandular trichomes on the veins, slightly pubescent on the spur, rarely strigose; inner surface villous behind the stamens, slightly pilose on the rest of the floral tube; petals 6, subequal, two dorsal ca. 2.7 × 0.9 mm, narrow-elliptic, four ventral ca. 3 × 1.1 mm, narrow-obovate; stamens free in the middle third of the floral tube, fully included; pistil 3–3.8 mm long; ovary glabrous; style pilose; ovules 3(–4); nectary ca. 0.6 × 0.3 mm, deflexed. Seeds 2–3, 1.7–2.5 × 1.5–2.2 mm, obovate, apex slightly truncate to obtuse, base slightly acute, margin obtuse.

Phenology: —Collected with flowers and fruits all year round.

Distribution and habitat: — Mexico, Central America, the Caribbean, Colombia, Venezuela, Guyana, Bolivia, Paraguay, and Brazil ( Fig. 23 ); disturbed places, such as roadsides and pastures, “campos sujos”, “veredas”, Amazonian savannas, and cerrado sensu stricto; 30–1500 m elev.

Conservation status: — Cuphea micrantha was categorized as Least Concern (LC) due to its wide geographic distribution, as well as being common and well-collected.

Representative specimens examined: —BOLIVIA. Santa Cruz: Andrés Ibáñez, Santa Cruz ca. 22 km hacia Abapó (Sud), 14 March 1981, Beck 6507 (P image!); José Miguel de Velasco, 50 km de Santo Antonio de Lomerío entre Santa Rosita y San Juan de Lomerío por el camino a Holanda, 17º03’18”S, 61º38’32”W, 01 June 2008, Wood et al. 25006 (CEN!). BRAZIL. Acre: Rio Branco, campo da Fazenda Capela, 01 September 1951, Black 51-13194 (CEN!, IAN!). Bahia: Rio de Contas, about 3 km N. of town of Rio das Contas, 21 January 1974, Harley et al. 15350 (NY image!, SPF!, UEC!). Ceará: Guaraciaba do Norte, Planalto da Ibiapaba, sítio Tamboatazinho, Cachoeira do Urubu, 04º12’04”S, 40º43’11”W, 30 April 2010, Brandão et al. 20 (HUEFS!, UFRN!). Distrito Federal: Brasília, Chapada da Contagem, estrada de terra à direita da rodovia, após povoado da Fercal II, 23 March 1997, Cavalcanti et al. 2178 (CEN!). Goiás: Jussara, estrada Jussara-Itapirapu ã, km 10, 15º51’00”S, 50º47’00”W, 16 March 1989, Cavalcanti et al. 445 (CEN!). Maranhão: Carolina, estrada BR-010-Goiatins, km 04, 07º24’09”S, 47º22’51”W, 20 January 2010, Pereira-Silva & Moreira 14975 (CEN!). Mato Grosso: Paranatinga, rodovia Paranatinga-Primavera do Leste (MT-130), Km 51, 14º52’39”S, 54º05’00”W, 07 April 2018, Pereira-Silva et al. 17081 (CEN!). Mato Grosso do Sul: Rio Brilhante, rodovia para Dourados, 21 February 1970, Hatschbach 23886 (MBM!, NY image!). Minas Gerais: Cabeceira Grande, cerrado que fica na estrada que dá acesso a AHE, ca. 1 km após Palmital, 16º09’00”S, 47º18’11”W, 18 February 2003, Santos & Pereira 1849 (CEN!); Mariana, rodovia MG-262, Ponte Nova-Ouro Preto, km 66, 20°22’00”S, 43°23’00”W, 09 February 1989, Scariot et al. 386 (CEN!); Salinas, Sítio 1, Ponto 5, 16°13’34”S, 42°22’56”W, 29 November 2016, Sevilha et al. 5872 (CEN!). Pará: Estreito-Marabá, Km 2, 07 April 1974, Pinheiro & Carvalho 364 (IAN!). Paraíba: Sert ã ozinho, Sítio Canafístula, 06°43’34”S, 35°26’42”W, 28 April 2018, Cordeiro 1325 (EAN image!). Pernambuco: Tapera, 27 August 1931, Pickel 2733 (US image!). Piauí: Altos, PI-221, Altos-Alto Longá, Km 1.5, 05º03’40”S, 42º25’52”W, 05 May 2018, Pereira-Silva et al. 17170 (CEN!). Rio Grande do Norte: Extremoz,APA de Jenipabu, trilha que leva ao segundo lago, 05º42’04”S, 35º12’29”W, 02April 2011, Jardim et al. 5960 (CEN!, UFRN!). Roraima: Boa Vista, BR-401 que liga Boa Vista-Bonfim, Km 3, 02º50’00”N, 60º40’00”W, 31 July 1986, Silva et al. 531 (INPA!, NY image!, UB!). São Paulo: Boa Esperança do Sul, 10 km NE of Boa Esperança do Sul on Jau-Araraquara road, and 7 km SW of km 103 marker, 10 March 1982, Graham 859 (MBM!, NY image!). Sergipe: Pirambu, Povoado Lagoa Redonda, 25 May 2012, Prata et al. 3079 (ASE image!). Tocantins: Palmeiras do Tocantins, estrada do rio Curicaca, a partir da BR-153, km 3.5, marcado do povoado, 06º38’46”S, 47º34’00”W, 12 January 2008, Pereira-Silva & Moreira 12556 (CEN!). CUBA. Pinar del Río: vicinity of Herradura, 26–30 August 1910, Britton et al. 6421 (NY image!); Pinar, west of S. Diego de los Baños, 21 August 1914, León 4442 (NY image!); La Chirigota, 09 August 1917, León 7462 (NY image!). DOMINICAN REPUBLIC. La Veja: Loma del Puerto, between La Vega and Jarabacoa, 31 August 1968, Liogier 12431 (NY image!). Santiago: San José, 05 August 1933, Valeur 950 (NY image!). EL SALVADOR. Morazán: Arambala, A.P. Río Sapo, cantón Cumaro, cerca del parqueo del ecoalbergue, 13°55’00”N, 88°06’00”W, 10 July 2003, Monterrosa S. & Rivera JMS00637 (MO image!). GUATEMALA. Jutiapa: 12 miles west of Jutiapa on Inter-American highway, 14°13’45”N, 90°04’42”W, 09 September 1964, Elias et al. 967 (MO image!). GUYANA. Upper Takutu-Upper Essequibo: Karanambo, 03º45’00”N, 59º20’00”W, 04 September 1988, Maas et al. 7243 (P image!); Konashen-area, Essequibo River, 01º34’00”N, 58º41’00”W, 25 September 1989, Jansen-Jacobs et al. 1831 (P image!). HONDURAS. Francisco Morazán: San Matías, N.O de Tegucigalpa, 12 October 1983, Torres 73 (MO image!). PARAGUAY. Amambay: Parque Nacional Cerro Corá, 22º38’00”S, 56º02’00”W, 08 February 1982, Solomon et al. 6834 (MO image!). Concepción: Loreto, a 5 km camino a San Luís, 23º14’00”S, 57º20’00”W, 23 November 1996, Molero & Duré 1040 (P image!). PUERTO RICO. Guanajibo, 26 December 1929, Britton & Britton 9396 (NY image!). VENEZUELA. Anzoátegui: El Tejero, carretera El Tejero-Barcelona, ca. 5 km del Tejero, 23 June 1983, Cardozo L. 525 (F image!). Miranda: carretera de Turmerito a Los Teques, 15 October 1939, Williams 12430 (F image!).

Cuphea micrantha is characterized by small floral tubes ( Fig. 12I, K ), 4–6 mm long, with an acute spur, and by stamens with filaments free in the middle third of the floral tube, fully included ( Fig. 12L ). Because of this last characteristic, it can be confused with C. inaequalifolia , which presents a variation in the position of the stamens inside the tube. Cuphea inaequalifolia differs from C. micrantha by the unequal pairs of bracts along the inflorescence, with one of the bracts greatly reduced in size, and by the strigose indumentum on the branches, with one-armed trichomes.

Cuphea micrantha can have bracteose inflorescences, with the vegetative leaves reduced distally on the stem to small bracts, and sometimes frondose, with vegetative leaves indistinct from the bracts, and is therefore often confused with C. carthagenensis (C. sect. Brachyandra ), which also has small floral tubes (4–6 mm long; Graham 2017). Cuphea micrantha is distinguished by the presence of 3(–4) ovules and obtuse margin seeds, while C. carthagenensis has 5–9 ovules and thinned margin seeds.

Cuphea micrantha used to belong to C. sect. Brachyandra ( Koehne 1903) , which is basically defined by the presence of stamens with very short filaments deeply inserted in the floral tube ( Koehne 1903 , Graham 1998a). Within this section, Koehne (1903) created C. sect. Brachyandra subsect. Micranthium to accommodate C. micrantha and C. tenuissima , united by the presence of 3 ovules and a deflexed nectary. Palynological ( Graham & Graham 1971, Graham 1998a) and molecular phylogenetic studies ( Graham et al. 2006, Barber et al. 2010, Cavalcanti, pers. comm.) revealed the artificiality of C. sect. Brachyandra and, in the revision of this section, Graham (2017) transferred the two species to C. sect. Trispermum .

Cuphea micrantha is the most widely distributed species of the section, occurring from Mexico to central South America, often behaving as a ruderal plant. The great success of its dispersal may be related to the autogamous mode of reproduction, due to the deep position of the stamens ( Graham 1998a). Autogamy is a remarkable characteristic of most invasive plants ( Baker 1974), which can produce seeds without the need for a pollinator, facilitating colonization and establishment in disturbed or anthropized areas.

Koehne (1903) listed C. hirta , C. euphorbioides , C. rapunculoides and Melanium hirtum as synonyms of C. micrantha . In the protologue of Melanium hirtum, Sprengel (1825) gives the minimalist type information “ Hispaniola . Portorico ”, omitting the name of the collector.A few years later, De Candolle (1828), when publishing his replacement name, gave some additional information: “ C. hirta [...]. in S.-Domingo. Bertero. Lythrum Domingense Spreng ! in herb. Balb. Melanium hirtum Spreng syst. 2. p. 454 ”. Although Sprengel (1825) omitted the collector, Melanium hirtum was based on collections by C.G. Bertero, as already indicated by De Candolle (1828). The other species listed by Koehne (1903) were kept in the synonymy after analysis of the type materials.

Cuphea valerii , synonymized by Graham (2009), was also confirmed as a synonym of C. micrantha in this revision. Because it differs from the typical species only in the presence of long, purplish trichomes, C. micrantha var. longeciliata was synonymized here.

Figures

FIGURE 12. A–H. Cuphea laricoides. A. Habit; B. Branch with brachyblasts; C–D. Branches with white (C) and lilac (D) flowers; E. Floral tube in lateral view, without petals; F. Floral tube in longitudinal-dorsal section, without petals; G. Pistil; H. Seed. I–N. Cuphea micrantha. I. Habit; J. Flower in lateral view and ruptured fruit with exposed placenta carrying a seed; K. Floral tube in lateral view, without petals; L. Floral tube in longitudinal-dorsal section, without petals; M. Pistil; N. Seed. A: Pereira-Silva et al. 17161; B, D, G, H: Pereira-Silva et al. 17160; C, E, F: Pereira-Silva et al. 17180; I: Pereira-Silva et al. 17081; K, M, N: Sevilha et al. 5872; L: Scariot et al. 386. Scale bar. E–G, L, M: 2 mm; H, N: 1 mm; K: 3 mm. Photo. J: Joel M.P. Cordeiro.

FIGURE 23. Geographical distribution of Cuphea micrantha.