Commelina obliqua Vahl, 1806

Commelina obliqua Vahl View in CoL

Figs 10–11 View Fig View Fig ; Table 3 View Table 3

Commelina obliqua Vahl ( Vahl 1806: 172) View in CoL . – Commelina erecta var. obliqua (Vahl) C.B.Clarke ( Clarke 1881: 181) View in CoL .

Commelinopsis glabrata D.R.Hunt (Hunt 1981: 195) View in CoL . – Commelina rufipes var. glabrata (D.R.Hunt) Faden & D.R.Hunt ( Faden & Hunt 1987: 122) View in CoL . – Type: TRINIDAD AND TOBAGO – Trinidad • Irois Forest district under cacao trees in quantities; 25 Jan. 1928; fl., fr.; W. E. Broadway 6716; holotype: K [ K000363259 ]!; isotype: BM [ BM000938214 ]!. Syn. nov.

Tradescantia portoricensis Bello (Bello 1883: 122) View in CoL . – Type: PUERTO RICO • Dorado forest; 28 Mar. 1966; fl., fr.; R. O. Woodbury s.n.; neotype: UPR [ UPR no. 06057]!, designated by Santiago-Valentín et al. (2015). Syn. nov.

Etymology

From the Latin ʻ oblīqua ʼ (meaning ʻslanting, awry, obliqueʼ), in reference to its oblique and asymmetrical leaf-blade base.

Type material

COUNTRY UNKNOWN • s.loc., cultivated in France, ex Horto Celsii ; s.dat.; fl.; Ventenat s.n.; lectotype: C [ C10009563 ]!, designated by Hunt (1994) .

Selected material examined

North America

MEXICO – Oaxaca • Itsmo de Tehuantepec, Juchitán de Zaragoza , La Ventosa ; 16 May 2014; fl.; F. Sánchez L. & P. Trujillo V. 815; MEXU, US .

West Indies

CUBA – Oriente • Sierra de Cristal , banks of Lebisa River ; 27 Dec. 1955; fl.; A.H. Liogier & M. López Figueiras 4618; MO, US .

DOMINICAN REPUBLIC – Samaná • La Vaca , N of Los Cacaos , Samaná Peninsula ; 15 Mar. 1969; fl., fr.; A.H. Liogier 14417; MO, US .

GRENADA – Saint George • Mt. Gilbert, NE of Mt. Maitland ; 4–10 Mar. 1979; fl., fr.; R.A. Howard & E.S. Howard 18794; NY .

PUERTO RICO – Utuado • Bo. Don Alonzo ; 9 Jan. 1999; fl.; P. Acevedo-Rodríguez 10534; JBSD, MAPR, NY, UPRRP , US.

TRINIDAD AND TOBAGO – Trinidad • St. George , Mount Tucuche; 9 Mar. 2006; fl., fr.; P.J.M. Maas et al. 9745; U , US.

Central America

BELIZE – Belize • Bermudian Landing, Belize River ; 25 May 1981; fr.; C. Whitefoord 3031; BM, MO, NO .

COSTA RICA – Limón • Canton de Talamanca, Fila Carbon, W of Cahuita ; 13 Feb. 1991; fl.; P.J.M. Maas 7905; MO, U, US .

EL SALVADOR – Ahuachapán • Sierra de Apaneca , in the region of Finca Colima ; 17–19 Jan. 1922; fr.; P.C. Standley 20203; F, US .

GUATEMALA – Huehuetenango • forested slopes in the vicinity of Ixcan , Sierra de los Cuchmantanes ; 27 Jul. 1942; fl.; J.A. Steyermark 49432; F .

HONDURAS – Cortés • Near Agua Azul; 27 Dec. 1947; fr.; L.O. Williams & A. Molina R. 11353 ; US.

NICARAGUA – Granada • Volcán Mombacho, Hacienda Las Delicias, ca 10 km al SE de ciudad Granada; 11 Oct. 1983; fr.; S. Vega & A. Grijalva 36; MO, US .

PANAMA – Panamá • Near Fort Randolph, Canal Zone ; 28 Dec 1923; fl.; P.C. Standley 28649; F, US .

South America

BOLIVIA – Beni • Yacuma, Estacion Biologica Beni Entrada El Triunfo ; 4 Jun. 1988; fl.; E. Villanueva & R. Foster 761; LPB, US .

BRAZIL – Bahia • Ilhéus, ca 22 Km na estrada Ilhéus/Serra Grande; 10 Aug. 1994; fl., fr.; A.M.V. de Carvalho et al. 4573; CEPEC, HUEFS, NY, RB .

COLOMBIA – Meta • 20 km SE of Villa Vicencia; 17 Mar. 1939; fr.; A.H. Alston 7575; BM, US .

ECUADOR – Guayas • Balao , in silvis gregaris; Dec. 1891; fl.; H.F.A. von Eggers 14141; L, US .

FRENCH GUIANA – Maripasoula • Mont Galbao , secteur Est. , Crète Nord-Sud ; 14 Jan. 1986; fr.; J.J. Granville et al. 8687; BR, CAY, MG, MO, NY, P, U, US .

GUYANA – East Berbice-Corentyne • Corentyne River ; Sep. 1879; fl.; E.F. Thurn s.n.; P [ P01795525 , P01795526 ] .

PERU – San Martín • Mariscal Cáceres, Dtto. Tocache Nuevo , Quebrada Ishichimi, cerca al Fundo del Sr. Luis Ludeña ; 9 Nov. 1980; fl., fr.; J. Schunke-Vigo 12409; RB, US 2ex.

SURINAME – Sipaliwini • Large island in Litani River , 6 km upstream from its confluence with Marowini River to form Lawa River; 1 Apr. 1998; fl., fr.; B. Hammel et al. 21225; MO, U 2ex.

VENEZUELA – Delta Amacuro • Mountain area ca 13 km by road ESE of the town of Sierra Imata; 4–6 Apr. 1979; fr.; G. Davidse & A.C. González 16612; MO, US, VEN .

Description

Herbs 30–120 cm tall, ascending to scrambling, perennial, robust, terrestrial or paludal. Roots fibrous, thin. Rhizome short. Stems monomorphic, ascending, branched; internodes 0.6–5.8 cm long, distally shorter, green, glabrous, sometimes with a line of acicular hairs opposite to the leaves, hairs hyaline or rusty to rusty-brown. Leaves distichously-alternate, evenly distributed along the stem, pseudopetiolate; sheaths 0.3–2.6 cm long, light green, generally suffused or speckled or longitudinally striated with magenta to red to vinaceous, sometimes completely magenta to red to vinaceous, glabrous, sometimes with a sparse setose line of hairs opposite to the leaves, hairs acicular, light brown to rusty, margin upright, glabrous to sparsely setose, hairs acicular, light brown to rusty; pseudopetiole 1.2–4.6 mm long; blades (1.3–1.9–)4.5–19.4 × (0.5–0.7–) 1.3–5 cm, lanceolate to ovate, sometimes elliptic, straight, thinly chartaceous to chartaceous, adaxially dark green to green, abaxially light green, adaxially glabrous to scabrid with prickle-hairs, abaxially glabrous, base asymmetric to strongly asymmetric, one side cuneate the other round, margin slightly revolute, glabrous to scabrid with prickle-hairs, apex acuminate to long-acuminate; midvein conspicuous, adaxially canaliculate, abaxially prominently obtuse, secondary veins 2–3 pairs, adaxially conspicuous, abaxially conspicuous, becoming more conspicuous on both sides when dry. Synflorescence composed of a solitary main florescence, restricted to the apex of the stems. Inflorescences terminal or apparently so, peduncle 0.2–1 cm long, shorter than ½ length of the spathe, straight, glabrous to puberulous with hook-hairs, sometimes with a line of acicular hairs opposite to the spathe, hairs hyaline; spathe 1.9–4.5 × 2.4–4.8 cm, very widely ovate to depressed ovate, patent to the peduncle, pale greenish-white to greenish-white to pale greenish-yellow, sometimes margin magenta to vinaceous, internally conspicuously mucilaginous, base only basally connate, splitting open and marcescent in fruit, subcordate, externally glabrous to ciliate with hook-hairs, hairs hyaline, margin flat, apex acuminate, slightly falcate, veins 5–6 pairs, conspicuous, becoming more conspicuous when dry; upper cincinnus developed, 2–6-flowered, flowers mainly staminate, rarely bisexual, peduncle 1.1–2.3 cm long, exserted, decurved at pre-anthesis and anthesis, sometimes strongly decurved to J-shaped at post-anthesis and fruit, sparsely to densely puberulous with minute hook-hairs, hairs hyaline; lower cincinnus 6–10-flowered, flowers mainly bisexual, sometimes staminate, peduncle 0.6–1.4 cm long, thickened in fruit, glabrous to sparsely puberulous with minute hook-hairs. Flowers chasmogamous, strongly zygomorphic, enantiostylous (style dislocated to the opposite side to the medial stamen); floral buds 1.9–6.3 × 2.3–7.1 mm, obovoid, light green to pale greenish-yellow to white, glabrous; pedicel 2.1–4.5 mm long, deflexed in bud and at anthesis, reflexed and elongating in fruit, light green to pale greenish-yellow, sparsely puberulous to puberulous with minute hook-hairs, hairs hyaline; sepals hyaline, early deciduous in fruit, dorsal sepal 4.3–5.2 × 2.4–3.5 mm, elliptic, concave, glabrous, apex acute, lower sepals 5.3–6.7 × 2.7–4.9 mm, shortly-clawed, connate up to mid-length, oblique-obovate, concave, glabrous, apex obtuse to round; paired petals 1–1.3 × 0.8–1 cm, clawed, claw 4.5–5.6 mm long, white, limb 5.4–6.9 × 7.9–9.6 mm, widely rhombic-reniform to reniform, white, base asymmetric, cordate, apex obtuse to slightly emarginate, medial petal 5.9–7.1 × 0.7–1.2 mm, sessile, lanceolate, entire, margin revolute at mid-length forming a medial constriction, concolourous with the paired petals, opaque, glabrous on both sides, apex acute to acuminate; staminodes (2–)3, medial staminode equal to the laterals, rarely medial staminode completely absent or greatly reduced and lacking the antherode, filaments 3.7–4.8 mm long, straight to arcuate-decurved, white, base sometimes pale greenish-yellow, antherodes 1.2–2.7 × 0.5–1.4 mm, narrowly hastate, pale yellow, minute pollen sacs between the upper and lower lobes present, non-polliniferous or producing very few grains, not apiculate between the upper lobes, upper lobes conspicuous, oblong, smaller than the lower, lower lobes oblanceolate; lateral filaments 5.9–8.2 mm long, very gently sigmoid to gently sigmoid, geniculate distal to the middle, apex recurved, white, base sometimes pale greenish-yellow, anthers 1.4–3 × 0.7–1.6 mm, held near the antherodes, elliptic to ovate, yellow, connective pale yellow to yellow, pollen pale yellow, drying yellow; medial filament 3.7–5.1 mm long, arcuate-decurved to gently sigmoid, apex recurved to strongly recurved, white, base sometimes pale greenish-yellow, anther 2.4–3.8 × 1.5–2.2 mm, held near the medial petal, widely sagittate, straight to slightly curved, pale yellow to yellow, connective saddle-shaped, pale yellow to yellow, anther sacs not appressed to each other, pollen pale yellow to yellow, drying yellow; ovary 1.2–1.4 × 1–1.3 mm, 3-carpellate, 5-ovulate, ellipsoid to widely ellipsoid, white to pale greenish-yellow, smooth, densely puberulous with glandular microhairs, style 5.3–7.1 mm long, exceeding the stamens, gently sigmoid to sigmoid, base cylindric, apex strongly recurved, white, base sometimes pale greenish-yellow, deciduous in fruit, stigma truncate, white. Capsules 6–9 per spathe, 5.3–7.1 × 4.2–5.8 mm, widely ellipsoid to widely oblongoid, short-stipitate, stipe 0.3–0.9 mm long, fruit wall thin, crustaceous, apex round, generally apiculate due to the persistent style base, not constricted between the seeds, pearly-white to silvery when mature, shiny, smooth, 3-locular, indehiscent, dorsal locule 1-seeded, ventral locules 2-seeded. Seeds monomorphic, 2.6–4.3 × 1.9–3 mm, the dorsal seed slightly larger than the ventral ones, all seeds adnate to the fruit wall and septa forming a dispersal unit, ellipsoid to triangular-ellipsoid, dorsally slightly flattened, ventrally pyramidal, not cleft towards the embryotega, dark grey to black, testa inconspicuously foveolate, non-farinose, embryotega lateral, inconspicuous, with a prominent apicule, hilum linear, longer than ½ the length of the seed.

Distribution

Commelina obliqua is widely distributed, extending from Mexico and the West Indies to Bolivia and Northeastern and Central-Western Brazil ( Fig. 11 View Fig ). The specimens cited by Pellegrini & Forzza (2017) for Southeastern Brazil (State of Rio de Janeiro) actually represent C. scabrata and, thus, are excluded from this species’ distribution range.

Ecology

It is found growing in the understory of rainforests and seasonally dry forests.

Phenology

It was found in bloom from March to December and with fruits from November to April.

Vernacular names

Trapoeraba branca ( Brazil), manobi-morotí ( Brazil), andacá-morotí ( Brazil), Anda ka’a morotî ( Brazil – Guarani), zapupa ( El Salvador).

Conservation

Commelina obliqua presents wide EOO (19 023 054 km 2) and AOO (ca 3624 km 2) and does not meet the thresholds for criterium B. There is no information on its populational trends or its current threats. Thus, following the IUCN (2012) criteria and the IUCN Standards and Petitions Committee (2024) recommendations, we suggest it should be considered as Least Concern (LC, criterium B).

Nomenclatural remarks

The name Commelina obliqua has, up until now, been erroneously applied to the blue-flowered species correctly named C. robusta . This confusion is rooted in Hunt (1981, 1983), which was posteriorly reinforced by Faden & Hunt (1987) and has survived up to now. Faden & Hunt (1987) reduced the genera Athyrocarpus , Commelinopsis and Phaeosphaerion to synonyms of Commelina based on the difficulty of differentiating these genera in the absence of fruiting material. Despite this being true and the gem-fruited species having evolved independently many times in Commelina (Pellegrini et al. in prep.), the gem-fruited species can be differentiated from closely related species based on vegetative, inflorescence and floral characters (see identification key). For instance, C. obliqua can be differentiated from C. robusta based on its pseudopetiolate leaves (vs sessile in C. robusta ), leaf-blade margin slightly revolute (vs flat), apex acuminate to long-acuminate (vs obtuse to acute), spathe slightly falcate (vs straight), only basally connate and subcordate (vs connate on the basal half to almost completely connate and truncate), much lighter than the leaves in vivo (vs the same colour as the leaves), the fused base splitting open in fruit (vs remaining fused), petals white (vs light blue to blue to sky blue or pale lilac to lilac), medial staminode aborted (vs present), and stigma trilobate (vs truncate).

Regarding fruit and seed morphology, C. robusta can be differentiated from C. obliqua based on its fruits being sessile, dehiscent, constricted between the seeds and tan-coloured or off-white when mature (vs short-stipitate, indehiscent, not constricted between the seeds, crustaceous and pearly-white to silvery when mature in C. obliqua ), seeds dimorphic, ellipsoid, ventrally flattened, not adnate to the fruit wall and septa and each dispersed individually (vs monomorphic, triangular, ventrally pyramidal, all adnate to the fruit wall and septa and forming a dispersal unit), and testa ornate (vs inconspicuously foveolate). While analysing the type specimen of C. obliqua , it became clear that it possesses pseudopetiolate leaves, leaf-blades with slightly revolute margins and long-acuminate apex, spathe slightly falcate, only basally connate with a subcordate base, petals white, and medial staminode aborted. Based on the aforementioned vegetative, inflorescence and floral characters, it was possible to confirm the type specimen of C. obliqua to be conspecific with the plants currently treated under C. rufipes var. glabrata . Thus, as the oldest validly published name at the species rank, C. obliqua is the correct name for the glabrous-leafed, white-flowered, white-fruited species of Neotropical Commelina .

Remarks

Commelina obliqua is morphologically most similar to C. pseudomonosperma and C. rufipes due to their leaf-blade margin being slightly revolute, spathe only basally connate, much lighter than the leaves in vivo, the fused base splitting open in fruit, pedicels sparsely puberulous to puberulous with minute hook-hairs, medial staminode aborted, style persistent in fruit, stigma truncate, fruits short-stipitate, indehiscent, not constricted between the seeds, crustaceous, pearly-white to silvery when mature; seeds monomorphic, triangular, ventrally pyramidal, all adnate to the fruit wall and septa and forming a dispersal unit, testa smooth ( Table 3 View Table 3 ). Recently, C. obliqua has erroneously been reduced to a synonym of C. rufipes based on their leaf-sheaths with rusty setose marginal hairs, white flowers, and indehiscent white fruits ( Hassemer 2020). However, C. obliqua is readily differentiated from C. rufipes by its leaf-sheaths glabrous, margin glabrous to setose, hairs light brown to rusty (vs hirsute throughout, hairs rusty to rusty-brown in C. rufipes ), blades lanceolate to ovate, sometimes elliptic, lustrous, thinly chartaceous to chartaceous (vs lanceolate to elliptic-lanceolate, opaque, membranous), adaxially glabrous to scabrid with prickle-hairs and abaxially glabrous (vs hispid on both sides, hairs hyaline, sparsely hirsute along the midvein and near the base, hairs rusty to rusty-brown), base asymmetric to strongly asymmetric, one side cuneate the other round (vs symmetric, cuneate to obtuse), apex acuminate to long-acuminate (vs acute), spathe very widely ovate to depressed ovate, glabrous, rarely with occasional hook-hairs (vs ovate to widely ovate, hispid with hyaline acicular hairs, sometimes with some rusty hirsute hairs), and medial petal lanceolate (vs very narrowly elliptic to narrowly elliptic) ( Table 3 View Table 3 ). Therefore, C. obliqua is reestablished by us as an accepted species based on consistent morphological characters. Furthermore, if the species in this complex were to be treated as conspecific, the name C. obliqua would take precedence over C. rufipes by around 50 years, requiring it to become the accepted name for these taxa.