Commelina huntii M.Pell.

Commelina huntii M.Pell. View in CoL

Figs 7–8 View Fig View Fig ; Table 2 View Table 2

Commelina huntii M.Pell. View in CoL (Pellegrini in Pellegrini & Forzza 2017: 67 View Cited Treatment , fig. 3–5).

Etymology

Named after the British botanist Dr David R. Hunt in recognition of his extensive contribution to Commelinaceae systematics worldwide, especially his contributions to Tradescantieae Meisn. and the gem-fruited Commelina .

Type material

BRAZIL – Rio de Janeiro • Itatiaia, Parque Nacional do Itatiaia , subida para o brejo da Lapa , beira de estrada ; 24 Jan. 2012; fl., fr.; M.O.O. Pellegrini & L.S. Sylvestre 191; holotype: RB [ RB01025642 ]!; isotypes: SPF !, US!.

Selected material examined

BRAZIL – Minas Gerais • Lima Duarte, Parque Estadual do Ibitipoca, Conceição do Ibitipoca , gruta do Pião ; 18 Jan. 2005; fl.; R.C. Forzza et al. 3926; RB, SPF, UEC . – Rio de Janeiro • Itatiaia, Parque Nacional do Itatiaia , estrada para parte alta , arredores do Brejo da Lapa , Floresta Ombrófila Densa Alto-Montana ; fl.; 7 Dec. 2017; M.B. Plumm et al. 102; RFA . – São Paulo • Itararé, divisa entre as Fazendas Santa Andreia e Prieto ; 14 May 1989; fl.; C.A.M. Scaramuzza & V.C. Souza 259; ESA .

Description

Herbs 15–50 cm tall, prostrate to ascending, perennial, delicate, terrestrial. Roots fibrous, thin. Rhizome short. Stems monomorphic, base prostrate, apex ascending, branched throughout; internodes 2.2–11.1 cm long, distally shorter, light green to green, minutely velutine to minutely pilose, with a line of acicular hairs opposite to the leaves, hairs hyaline. Leaves distichously-alternate, slightly congested at the apex of the stem, sessile; sheaths 1.4–2.6 cm long, light green, sometimes suffused purple or vinaceous, longitudinally striated green, pilose, hairs acicular, hyaline, with a line of setose hairs opposite to the leaves, hairs acicular, rusty to rusty-brown, margin upright, densely setose, hairs acicular, rusty to rusty-brown; blades 3.3–11.6 × (0.9–) 1.6–3.3 cm, lanceolate to ovate-lanceolate, rarely ovate, straight, chartaceous, adaxially dark green to green, abaxially light green to light green tinted vinaceous to completely vinaceous, adaxially scabrid with prickle-hairs, abaxially minutely villous, pilose along the midvein, hairs hyaline, base asymmetric, obtuse, rarely cuneate, margin flat, scabrid with prickle-hairs, apex acuminate; midvein conspicuous, adaxially impressed, abaxially prominently obtuse, secondary veins (3–)4–6 pairs, adaxially conspicuous, abaxially inconspicuous, becoming more conspicuous on both sides when dry. Synflorescence composed of a solitary main florescence or main florescence plus 1–3 co-florescences, restricted to the apex of the stems. Inflorescences terminal or apparently so, peduncle 1.3–5.5 mm long, rarely inconspicuous, shorter than ½ length of the spathe, straight, puberulous to densely puberulous with minute hook-hairs, hairs hyaline; spathe 0.7–2 × 1.4–3.2 cm, depressed ovate to subcordate, patent to the peduncle, concolourous with the leaves, internally conspicuously mucilaginous, base connate up to mid-length, truncate to subcordate, externally minutely villous with eventual cilia, hairs hyaline, cilia rusty to rusty-brown, margin flat, apex obtuse to acute, usually slightly falcate, veins 3–4 pairs, inconspicuous, becoming conspicuous when dry; upper cincinnus developed, 2–5-flowered, flowers mainly staminate, sometimes bisexual, peduncle (0.7–) 1.7–2.4 cm long, exserted, gently decurved at pre-anthesis, anthesis, post-anthesis and fruit, sparsely to densely puberulous with minute hook-hairs, hairs hyaline; lower cincinnus 2–4-flowered, flowers mainly bisexual, sometimes staminate, peduncle 0.5–1 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 3.1–4.4 × 1.6–3.2 mm, obovoid, white to light green, glabrous; pedicel 1.6–4.7 mm long, deflexed in bud and at anthesis, reflexed and elongating in fruit, light green, glabrous; sepals hyaline, persistent and accrescent in fruit, dorsal sepal 3.4–4.2 × 1.1–1.4 mm, elliptic, concave, glabrous, apex round, lower sepals 4.1–6.2 × 2.2–3.9 mm, shortly-clawed, connate up to mid-length, oblique-obovate, glabrous, apex round; paired petals 4.2–6.9 × 3.2–5.4 mm, clawed, claw 1.1–2 mm long, white to pale vinaceous, limb 3.9–5.3 × 3.2–5.4 mm, widely rotund to rotund-reniform, white, base asymmetric, subcordate to cordate, apex round to slightly emarginate, medial petal 3.1–4 × 1–1.4 mm, sessile, oblong to oblong-spathulate, 2-auriculate, apex involute, concolourous with the paired petals, hyaline, glabrous on both sides, apex obtuse to round; staminodes 3, medial staminode equal to the laterals, filaments 2.8–3.6 mm long, arcuate-recurved, apex recurved to strongly recurved, white, tan-coloured to vinaceous, antherodes 1–1.2 × 1.2–1.6 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, very widely obovate, larger than the lower, lower lobes widely obovate; lateral filaments 5.1–6.6 mm long, gently sigmoid, geniculate distal to the middle, apex recurved, white, base light green, apex tan-coloured to vinaceous, anthers 1.1–1.6 × 0.5–1 mm, held near to the medial anther, oblong to elliptic, pale orange-yellow to pale apricot-coloured, margin tinted purple to atro-purpureous, connective pale orange-yellow to pale apricot-coloured, margin tinted purple to atro-purpureous, pollen yellowish-orange to cream-orange, drying orange-yellow to pale apricot; medial filament 2.2–2.8 mm long, straight to arcuate-recurved, apex recurved to strongly recurved, white, apex sometimes tan-coloured to vinaceous, anther 1.5–2.6 × 1.3–2.4 mm, held near the antherodes and lateral anthers, widely oblong to widely elliptic, slightly curved, pale orange-yellow to pale apricot, connective shield-shaped, pale orange-yellow to pale apricot, with a vinaceous to atro-vinaceous spot at centre, anther sacs not appressed to each other, pollen yellowish-orange to cream-orange, drying orange-yellow to pale apricot; ovary 0.9–1.4 × 0.6–1 mm, 3-carpellate, 5-ovulate, oblongoid, light green, sparsely papillose, papillae black, puberulous with glandular microhairs, style 7.3–11.3 mm long, equalling or exceeding the stamens, sigmoid, base cylindric, apex strongly recurved, white, base light green, apex tan-coloured, deciduous in fruit, stigma trilobate, white. Capsules 1–2 per spathe, 5.5–8.1 × 3.9–5 mm, obovoid, sessile, fruit wall thin, apex truncate to round, constricted between the seeds, tan-coloured when mature, shiny, sparsely papillose, papillae black, 3-locular, unequally 2-valved, dorsal locule 1-seeded, indehiscent, ventral locules 2-seeded, dehiscent, valves splitting to base. Seeds dimorphic, dark brown with orange-brown verrucae; dorsal locule seed 3.4–4.2 × 2.8–3.3 mm, adnate to the fruit wall, ellipsoid, strongly dorsiventrally compressed, ventrally flattened, not cleft towards the embryotega, testa shallowly foveolate, non-farinose, embryotega semilateral, inconspicuous, without a prominent apicule, hilum linear, ca ½ the length of the seed, on a weak ridge; ventral locule seeds 2.7–4 × 2–2.4 mm, free from the fruit wall, ellipsoid, truncate at one end, ventrally flattened, not cleft towards the embryotega, testa foveolate, sparsely farinose, farinae apricot, embryotega semilateral, inconspicuous, without a prominent apicule, hilum curved, ca ½ the length of the seed, on a weak ridge.

Distribution

Endemic to the states of Minas Gerais, Rio de Janeiro, and São Paulo, Brazil ( Fig. 8 View Fig ).

Ecology

Commelina huntii grows in the understory of moist and shaded nebular forests in the Atlantic rainforest biome, generally near water bodies at elevations from 800 to 1700 m above sea level. In rare cases, it can also be found in open, sometimes disturbed, areas.

Phenology

Commelina huntii blooms from November to June and fruits from December to March, rarely in June.

Vernacular names

Trapoeraba branca ( Brazil), trapoeraba da Bocáina (Brazil) .

Conservation

Despite the wide EOO (130 546 km 2), the AOO (ca 196 km 2) is considerably reduced. Following the IUCN (2012) criteria and the IUCN Standards and Petitions Committee (2024) recommendations, Pellegrini & Forzza (2017) suggested C. huntii should be considered Endangered (EN), but with the incorrect criteria and subcriteria. Observed populations tend to have few mature individuals (ca 40), and clonal reproduction seems to be the prevalent and most successful strategy (Pellegrini, pers. obs.). Populations are commonly threatened by a decrease in habitat quality (mainly due to competition with invasive species) and deforestation. Thus, based on updated and improved data, we update and improve the conservation assessment for C. huntii as Endangered (EN) based on further criteria [B2ab(ii, iii), c(iv)+C2a(i)].

Remarks

Commelina huntii can be recognised by its white flowers with an auriculate medial petal and sparsely papillose ovary and capsules. It is similar to C. obliqua and C. rufipes due to their white flowers and rusty hairs on the leaf-sheaths. However, it can be readily distinguished from both species by its spathe base connate for 3–6 mm (vs only basally connate), auriculate medial petal without a medial constriction (vs entire with a constriction in C. obliqua —previously known as C. rufipes var. glabrata (D.R.Hunt) Faden & D.R.Hunt ; see comments below—, and entire without a medial constriction in C. rufipes ), fruits dehiscent, ellipsoid, tan-coloured and not crustaceous (vs indehiscent, pearly-white to silvery and crustaceous for both species, widely ellipsoid to widely oblongoid in C. obliqua , and subglobose to globose in C. rufipes ), and by its free and ornamented seeds (vs seeds adnate to the fruit septa, forming a dispersal unit, with smooth to inconspicuously foveolate testa).

Commelina huntii is most similar to C. robusta Kunth due to its oblique leaf-blades, persistently connate spathe base, dehiscent capsules, and ventral seeds free with foveolate testa ( Table 2 View Table 2 ). Nevertheless, C. huntii can be distinguished by its densely setose leaf-sheath margin with rusty to rusty-brown hairs (vs leaf-sheath margin long-ciliate with red to dark red to atro-vinaceous hairs in C. robusta ), petals white (vs blue to light blue to lilac to pale lilac), paired petals limb widely rhombic to rhombic reniform (vs widely ovate to widely ovate reniform), medial petal concave and 2-auriculate (vs involute and entire), anthers of the lateral stamens light yellow to cream-coloured with margin tinted vinaceous (vs completely orange); ovary and capsules sparsely black papillate (vs smooth), 1–2 capsules per spathe (vs 5–7), seeds with apricot-coloured farinae (vs seeds white-farinose), and dorsal locule seeds with shallowly foveolate testa (vs rugose-foveolate testa) ( Table 2 View Table 2 ).