Commelina robusta Kunth, 1843

Commelina robusta Kunth View in CoL

Figs 14–15 View Fig View Fig ; Table 2 View Table 2

Commelina robusta Kunth ( Kunth 1843: 52) View in CoL .

Commelina bambusifolioides Matuda ( Matuda 1955: 62) View in CoL . – Type: GUATEMALA – Jutiapa • Between Jutiapa and La Calera, southeast of Jutiapa ; 2 Nov. 1940; fl., fr.; P. C. Standley 76117; holotype: F [ V0045319 F]!. Syn. nov.

Commelina monticola Seub. View in CoL ( Seubert in Martius 1855: 264). – Type: BRAZIL – Minas Gerais • s.loc.; Aug. 1840 – Apr. 1841; fl.; P. Claussen 420; holotype: BR [ BR0000021451010 ]!. Syn. nov.

Commelina vilavelhensis D.Maia et al. ( Maia et al. 2012: 294) View in CoL . – Type: BRAZIL – Paraná • Ponta Grossa, Parque Estadual de Vila Velha; 26 Nov. 2005; fl.; D. Corrêa da Maia 41; holotype: UPCB [†]; isotypes: HUPG [†], MBM [†]; lectotype: original illustration by D. Maia and later published in Maia et al. (2012), designated by Hassemer et al. (2016). Syn. nov.

Etymology

The epithet derives from the Latin ʻ rōbur ʼ (a kind of hard oak, or meaning ʻhardness, strengthʼ) + the suffix ʻ -ta ʼ (meaning ʻprovided withʼ), in reference to this species’ large stature (i.e., strong growth).

Type material

BRAZIL – Rio de Janeiro • Brasilia meridionalis, Paraíba do Sul ; Dec. 1836; fl., fr.; F. Sellow B. 1308-C.293; B [ B100296353 ] !.

Selected material examined

North America

MEXICO – Chiapas • Anel Albino Corzo, slopes with Pinus and Quercus , 3–5 km above Jaltenango along the road to Finca Prusia; 11 Oct. 1974; fl.; D.E. Breedlove 38595; K .

West Indies

TRINIDAD AND TOBAGO – Trinidad • Maracas waterfall ; 10 Apr. 1920; fl.; N.L. Britton et al. 1645; NY, US .

Central America

COSTA RICA – Cantón de San Ramón • Cuenca del San Carlos, Los Angeles, 2 km antes del Rio Cataratitas, ruta a Bajo Rodriguez ; 28 Jan. 1997; fl., fr.; A. Rodriguez & V.H. Ramirez 1941; INB, K 3ex, MO .

EL SALVADOR – Santa Ana • Metapan, Hacienda San José ; 23 Aug. 1951; fl.; O. Rohweder 873; HBG, MO .

GUATEMALA – Jutiapa • Between Jutiapa and La Calera , southeast of Jutiapa ; 2 Nov. 1940; fl.; P.C. Standley 76117; F .

NICARAGUA – Nueva Segovia • 7 km S of La Jungla; 31 Jan. 2010; fl., fr.; W.D. Stevens et al. 29318; HULE, MO .

South America

ARGENTINA – Misiones • Dep. Candelaria ; Alrededores de Loreto , selva secundaria con pequeno arroyo ; 25 Mar. 1996; fl.; S.G. Tressens et al. 5536; CTES, K 2ex.

BOLIVIA – La Paz • Prov. Nor Yungas, bajando por Caranavi , de Yolosa 46 km y entrando por San Pedro de León, al lado del rio San Pedro ; 2 Jun. 1983; fl., fr.; G. Beck 9206; K, UMSA, US .

BRAZIL – Rio de Janeiro • Petrópolis, Quitandinha, Pedra do Quitandinha ; 2 May 2010; fl., fr.; M.O.O. Pellegrini 2; RFA .

COLOMBIA – Cundinamarca • Guarama near San Francisco ; 27 Mar. 1983; fl., fr.; J.R.I. Wood 3567; FMB, K 3ex.

ECUADOR – Zamora-Chinchipe • Along road between Zumba and Vilcabamba , 57.9 km N of Zumba, 9.2 km S of Santa Ana, 6.3 km N of Palanda; 28 Jul. 2004; fl., fr.; T.B. Croat 92498; AAU, MO, US .

PARAGUAY – Guaira • Cordillera de Ybytyruzú , Melgarejo-Cerro Acati , 4km S of Melgarejo on Arroyo Tacuara; 10 Jul. 1992; fl.; E. Zardini & P. Aquino 32579; FCQ, MO, RB, US .

PERU – Cajamarca • San Ignacio, San José de Lourdes ; 16 Feb. 2000; fl., fr.; J. Campos & R. Vásquez 6435; K, MO, US .

VENEZUELA – Trujillo • Boconó , Parque Nacional Guaramacal , Laguna de Aguas Negras , cerca de Batatal ; 23 Sep. 2000; fl.; M. Niño et al. 1345; PORT, US .

Description

Herbs 40–250 cm tall, prostrate, ascending or scrambling, perennial, robust, rupicolous, terrestrial or paludal, rarely epiphytic. Roots fibrous, thin. Rhizome short. Stems monomorphic, base prostrate, apex prostrate, ascending or scrambling, branched throughout or branched in the upper third; internodes 0.5– 18.5 cm long, distally shorter, light green to green, sometimes suffused with red to vinaceous, glaucous, glabrous to scabrid with prickle-hairs, hairs hyaline. Leaves distichously-alternate, slightly congested at the apex of the stem, pseudopetiolate; sheaths 0.7–6.5 cm long, light green, suffused with red, to vinaceous to atro-purpureous, glaucous, scabrid with prickle-hairs, sometimes with a line of hirsute hairs opposite to the leaves, hairs acicular, red to dark red to atro-vinaceous, margin upright, hirsute, hairs acicular, red to dark red to atro-vinaceous; pseudopetiole 0.1–1.1 cm long; blades (2.5–)3.2–16.2 × 0.8–4.6 cm, lanceolate to ovate, straight, thinly chartaceous, sometimes chartaceous, adaxially dark green to green, abaxially light green, adaxially scabrid with prickle-hairs, abaxially scabrid with prickle-hairs to pilose with acicular hairs, hairs hyaline, base asymmetric, obtuse to round, margin flat, scabrid with prickle-hairs, apex obtuse to acute; midvein conspicuous, adaxially impressed, 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 or main florescence plus 1–10 co-florescences, restricted to the apex of the stems. Inflorescences terminal or apparently so, peduncle 0.3–1.8 cm long, shorter than ½ length of the spathe, straight, scabrid with prickle-hairs, hairs hyaline; spathe 0.9–3.4 × 2–4.3 cm, depressed ovate to widely depressed ovate, rarely very widely ovate, patent to the peduncle, concolourous with the leaves, internally conspicuously mucilaginous, base connate up to mid-length, truncate, externally scabrid with prickle-hairs, hairs hyaline, margin flat, apex obtuse to round, sometimes subtruncate, straight, veins 3–4 pairs, inconspicuous, becoming more conspicuous when dry; upper cincinnus developed, 2–6-flowered, flowers mainly staminate, sometimes bisexual, peduncle 1.1–4.2 cm long, exserted, straight at pre-anthesis, anthesis, post-anthesis and fruit, puberulous with minute hook-hairs, hairs hyaline; lower cincinnus 3–7-flowered, flowers mainly bisexual, sometimes staminate, peduncle 0.6–1.8 cm long, thickened in fruit, puberulous with minute hook-hairs. Flowers chasmogamous, strongly zygomorphic, enantiostylous (style dislocated to the opposite side to the medial stamen); floral buds 1.6–7.1 × 1.1–7.7 mm, obovoid, light green or white to light blue, glabrous; pedicel 0.4–4.8 cm long, deflexed in bud and at anthesis, reflexed and elongating in fruit, light green, glabrous; sepals hyaline, persistent and accrescent in fruit, dorsal sepal 2.1–4.6 × 1.7–3.2 mm, triangular to widely triangular, concave, glabrous, apex obtuse, lower sepals 3.9–6.8 × 2.3–5.1 mm, shortly-clawed, connate up to mid-length, oblique-obovate to widely oblique-obovate, concave, glabrous, apex obtuse; paired petals 0.8–1.4 × 0.5–1.4 cm, clawed, claw 1.4–4.7 mm long, pale vinaceous, limb 7.6–14.2 × 5.4–13.8 mm, very widely ovate-reniform to depressed ovate-reniform, light blue to blue to lilac-blue or pale lilac to lilac, rarely white, base asymmetric, cordate to sagittate, apex obtuse to round to slightly emarginate, medial petal 5.7–8.3 × 1.9–3.8 mm, sessile, spathulate to obovate, entire, completely involute, discolourous with the paired petals, light blue to pale lilac, hyaline, adaxially glabrous, abaxially puberulous at base with glandular microhairs, apex obtuse; staminodes 3, medial staminode equal to the laterals, filaments 2.3– 4.7 mm long, straight to arcuate-decurved, vinaceous, base white to tan-coloured, apex burgundy to atro-vinaceous, antherodes 0.6–1.4 × 0.7–1.8 mm, X-shaped, 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, obovate, shorter than the lower, lower lobes spathulate to obovate; lateral filaments 5.2–9.1 mm long, gently sigmoid to sigmoid, geniculate distal to the middle, apex recurved, vinaceous, base white to tan-coloured, apex sometimes tan-coloured to burgundy, anthers 1.1–1.5 × 0.6– 0.9 mm, held near the medial anther, elliptic to ovate, orange-yellow to orange, orange-yellow to orange, pollen orange-yellow to orange, drying orange to buff-orange; medial filament 3.1–6.8 mm long, arcuate-recurved to gently sigmoid, apex strongly recurved, vinaceous, base white to tan-coloured, apex burgundy to atro-vinaceous, anther 1.4–2.1 × 1.1–2 mm, held near the lateral anthers, widely oblong to widely elliptic, slightly curved, orange-yellow to orange, connective shield-shaped, orange-yellow to orange, with an atro-vinaceous to maroon spot at centre, anther sacs not appressed to each other, pollen orange-yellow to orange, drying orange to buff-orange; ovary 1.5–2.3 × 0.8–1.6 mm, 3-carpellate, 5-ovulate, ellipsoid to widely ellipsoid, green, smooth, puberulous with glandular microhairs, style 5.9–10.3 mm long, equalling or slightly exceeding the stamens, sigmoid, base cylindric, apex strongly recurved, vinaceous, base white to tan-coloured, apex tan-coloured, deciduous in fruit, stigma trilobate, white to tan-coloured. Capsules 3–5 per spathe, 6.7–10.3 × 4.1–6.9 mm, obovoid, sessile, fruit wall thin, apex truncate, constricted between the seeds, tan-coloured when mature, shiny, smooth, 3-locular, unequally 2-valved, dorsal locule 1-seeded, indehiscent, ventral locules 2-seeded, dehiscent, valves splitting to the base. Seeds dimorphic, brown to dark brown; dorsal locule seed 4.1–5.3 × 2.4–3.8 mm, adnate to the fruit wall, widely ellipsoid, dorsiventrally compressed, ventrally flattened, slightly cleft towards the embryotega, testa foveolate, non-farinose, embryotega semilateral, inconspicuous, with a prominent apicule, hilum linear, ca ½ the length of the seed, on a weak ridge; ventral locule seeds 3.3–5.1 × 2–3.4 mm, free from the fruit wall, ellipsoid to reniform, truncate at one end, ventrally flattened, not cleft towards the embryotega, testa rugose-foveolate, sparsely farinose, farinae white, embryotega semilateral, conspicuous, with a prominent apicule, curved, ca ½ the length of the seed, on a strong ridge.

Distribution

From Mexico to Argentina. In Brazil, it is recorded for all regions and States, except for Acre, Amazonas, and Roraima ( Fig. 15 View Fig ).

Ecology

Commonly found growing in shady, disturbed areas such as roadsides, gardens and forest margins, and agricultural fields. It is less commonly found growing in drier regions and rocky outcrops.

Phenology

Throughout the year, especially during the rainy season.

Vernacular names

Trapoeraba gigante ( Brazil), trapoeraba-açu ( Brazil), batata-ovo ( Brazil), manobi-açu ( Brazil), andacáaçu ( Brazil), Anda ka’a açu ( Brazil – Guarani).

Uses

Used in traditional medicine and occasionally as food in Brazil. The mucilage secreted by damaged stems is used pure or diluted in water to remove warts or the dermatological bleaching of dark spots and markings. Cooked stems are used to treat dysentery and are occasionally eaten as greens. The infusion prepared using this plant is used in the traditional treatment of ophthalmias ( Corrêa 1975; Pellegrini, pers. obs.).

Conservation

Commelina robusta presents a vast extent of occurrence (EOO = 20 747 654 km 2), also occupying a large area (AOO = ca 8540 km 2), and the species does not meet the thresholds for criterium B. The observed populations are large and stable, with several mature individuals and no evidence of current threats. Thus, following the IUCN (2012) criteria and the IUCN Standards and Petitions Committee (2024) recommendations, C. robusta should be considered as Least Concern (LC, criterium B).

Nomenclatural remarks

As aforementioned, the type of C. obliqua clearly matches C. rufipes var. glabrata , as circumscribed by Faden & Hunt (1981). Faden (in Faden & Hunt 1981) informally proposes the synonymisation of C. robusta under C. obliqua based on his examination of the type specimen of the latter. Despite the unquestionable contributions to the taxonomy and nomenclature presented in Faden & Hunt (1981), the authors fail to realise the conspecificity of C. obliqua and C. rufipes var. glabrata when proposing this new synonym, thus creating further confusion on the identity and application of C. obliqua and C. robusta . However, as aforementioned, the type specimen of C. obliqua disagrees with the current concept of the name, matching that of C. rufipes var. glabrata instead. Alternatively, the type specimen of C. robusta is well-preserved and contains detailed sketches done by Kunth. The type specimen, together with Kunth’s drawings and the species’ original publication, leaves no doubt of this name’s identity and application.

Remarks

Commelina robusta is morphologically similar to C. vestita due to their gross morphology, involute and entire medial petal, ovary and capsules smooth, seeds white-farinose, and dorsal seed with testa rugose-foveolate ( Table 2 View Table 2 ). However, C. robusta can be differentiated from C. vestita by its robust stature (vs delicate in C. vestita ), stems prostrate to ascending to scrambling, sometimes erect, branched throughout or branched in the upper third, scabrid to glabrous (vs ascending to erect, unbranched to branched at base, velutine to hispid), leaf-sheath margin with red to dark red to atro-vinaceous hairs (vs hairs light brown to brown), blades abaxially light green (vs vinaceous to dark purple), spathe glabrous on both sides, margin setose near the base (vs externally velutine to hispid, internally sparsely velutine, margin glabrous), dorsal sepal triangular to widely triangular (vs elliptic to ovate), paired petals limb very widely ovate-reniform to depressed ovate-reniform (vs ovate-reniform to widely ovate-reniform), medial petal spathulate to obovate, light blue to pale lilac, completely involute (vs petal oblong to oblanceolate, white, apex involute), antherodes not apiculate between the upper lobes (vs apiculate between the upper lobes), anthers orange-yellow to orange (vs pale orange-yellow to pale apricot), and lateral anthers held near the medial anther (vs held near the stigma) ( Table 2 View Table 2 ).

A great deal of morphological variation was recognised in the previous circumscription of C. robusta (until now treated as C. obliqua ). It comprised plants from small to large stature (sometimes way over 1.5 m tall), stems from creeping with ascending apex to erect to scandent, and thin and fibrous to robust and somewhat succulent stems. The leaves ranged from 4–20 cm long, from glabrous to scabrid to pilose, and from light green to vinaceous abaxially. Flower size and colour also varied immensely and were regarded as environmental ( Pellegrini & Forzza 2017). On the other hand, Pellegrini & Forzza (2017) also stated that it represented a Pantropical species complex, but that was the best way to deal with this taxon at the time. The synonymy proposed by Hassemer (2020, and references therein) has been carefully reviewed by us and revealed the need to reestablish several names. Alternatively, C. bambusifolioides , C. monticola , and C. vilavelhensis are confirmed to be conspecific with C. robusta . This decision is supported by the vegetative and reproductive morphology observed in the type specimens and retrieved from their original publications and illustrations. We have been able to recognise and segregate C. bambusifolia , C. scabrata , C. sugariae sp. nov., and C. vestita , aside from C. huntii and C. robusta . The differentiation between these taxa has previously not been possible due to the lack of fieldwork and proper study of the type specimens and protologues. However, new data made available to MOOP since 2017 has proven key to recognising these species based on macro-morphology. Characters such as leaf-blade architecture, pubescence, degree of connation of the spathe base, development of the upper cincinnus, lower cincinnus pubescence, lower sepals connation, paired petal limb base, the colouration of the medial connective, and fruit and seed morphology have proven key to differentiating these taxa.

Despite our current efforts and updates, which have allowed the recognition of a much more welldelimited taxon, C. robusta remains polymorphic, and further studies are still necessary to finesse its circumscription (see Remarks on C. mathewsii (C.B.Clarke) Faden & D.R.Hunt ).