Commelina huntii M.Pell., 2017

Pellegrini, Marco Octavio de Oliveira & Forzza, Rafaela Campostrini, 2017, Synopsis of Commelina L. (Commelinaceae) in the state of Rio de Janeiro, reveals a new white-flowered species endemic to Brazil, PhytoKeys 78, pp. 59-81 : 62-65

4. Commelina huntii M.Pell. sp. nov. Figs 3 , 4 , 5

Diagnosis.

Commelina rufipes Seub. affinis, sed ab ea spathis depressum-ovatum vel sub-cordato, basi adnata, petalo inferioris auriculata, ovarium sparse nigro-papillose, capsulae ellipsoide dehicens, parda, seminibus libera differt.

Holotype.

BRAZIL. Rio de Janeiro: Itatiaia, Parque Nacional do Itatiaia, subida para o brejo da Lapa, beira de estrada, fl., fr., 24 January 2012, M.O.O. Pellegrini & L.S. Sylvestre 191 (RB!; isotypes: SPF!, US!).

Description.

Herbs 15-35 cm tall, perennial, terrestrial. Roots thin, fibrous, cream colored to light yellow, glabrous or minutely pubescent with absorbent hairs. Stems decumbent, apex ascending, becoming trailing or straggling, rooting only near the base; internodes 2.2-11.1 cm long, green, minutely velutine to minutely pilose, with line of uniseriate hairs opposite to the leaves, hairs hyaline. Leaves distichously-alternate, distributed along the stem, sessile; sheaths 1.4-2.6 cm long, pilose, hairs hyaline, margins densely setose, with a line of setose hairs opposite to the leaves, hairs rusty to rusty-brown; blades 3.3-9.1 × (0.9-)1.6-2.3(-3.3) cm, chartaceous, adaxially dark-green to green, abaxially light-green to light-green tinted vinaceous to completely vinaceous, drying olive-green on both sides, lanceolate to ovate lanceolate, rarely ovate, adaxially scabrous, abaxially minutely villous, pilose along the midvein, hairs hyaline, base obtuse, rarely cuneate, margins green, scabrous, apex acuminate; midvein conspicuous, impressed adaxially, prominently obtuse abaxially, secondary veins (2-)4-6 pairs, adaxially conspicuous, abaxially inconspicuous. Inflorescences 1-4, terminal or apparently so, peduncles 1.3-5.5 mm, rarely inconspicuous, puberulous with hook hairs throughout, hairs hyaline; spathes 0.7-2 × 1.4-3.2 cm, depressed ovate to subcordate, usually slightly falcate, base connate for 3-6 mm, cordate to truncate, margin green to vinaceous, minutely pilose along the edge, hairs hyaline, sometimes also ciliate, cilia rusty to rusty-brown, apex acute, internally light-green, glabrous, veins inconspicuous, externally green, minutely villous with eventual cilia, hairs hyaline, cilia rusty to rusty-brown, veins inconspicuous, becoming conspicuous when dry; upper cincinnus 2-5-flowered, flowers male, very rarely bisexual, peduncle (0.7-)1.7-2.4 cm long, exserted from the spathe, commonly arcuate at post-anthesis, sparsely to densely puberulous with hook hairs, sometimes of 2 heights, hairs hyaline; lower cincinnus 2-4-flowered, flowers mainly bisexual, sometimes male, peduncle 0.5-1 cm, glabrous or sparsely puberulous with minute hook hairs. Flowers bisexual or male, zygomorphic, 6.5-9 mm diam.; pedicel 1-4 mm long, light green, glabrous, reflexed and slightly elongate in fruit; sepals hyaline white to hyaline light-green, glabrous, persistent in fruit, upper sepal 3,4-4,2 × 1,1-1,4 mm, elliptic, cucullate, round apex, lower sepals 4.1-5.3 × 2.2-2.6 mm, obovate, cucullate, connate, round apex; paired petals 6.2-6.9 × 4.9-5.4 mm, clawed, limb broadly rhomboid to rhomboid-reniform, 4.7-5.3 × 4.9-5.4 mm, white, apex rounded, base cordate, claw 1.6-2 mm, white to tinted vinaceous, medial petal 3.1-4 × 1-1.4 mm, sessile, obovate to oblong-obovate, with 2 auricles near the middle, cucullate, concolorous with or slightly paler than the paired petals; staminodes 3, subequal, filaments 3-3.6 mm long, tinted vinaceous, antherodes 6-lobed, 1-1.2 × 1.2-1.4 mm, yellow with tiny light-yellow pollen sacs; lateral stamen filaments gently sigmoid, geniculate distal to the middle, 5.6-6.6 mm long, white, anthers elliptic to oblong-elliptic, 1.2-1.4 × 0.9-1.2 mm, yellowish-orange to cream-orange with margins tinted purple, pollen yellowish-orange to cream-orange; medial stamen filament straight or arcuate-decurved, decurved at the apex, 2.2-2.8 mm long, white to tinted vinaceous, anther 1.5-2.2 × 1-1.8 mm, broadly elliptic to broadly oblong-elliptic, strongly curved, held near the antherodes, yellow-orange to cream-orange, connective purple to dark-purple, pollen yellowish-orange to cream-orange; ovary oblong-ellipsoid, ca. 1-1.3 × 0.6-0.7 mm, 5-ovulate, glabrous, sparsely papillose, papillae black, style exceeding or equaling the stamens, sigmoid, strongly recurved apically, 8-11.3 mm, white, stigma trilobate, white. Capsules 1-2 per spathe, 5.5-8.1 × 3.8-5 mm, obovoid, constricted between the seeds, brown to light brown, glabrous, sparsely papillose, papillae black, 3-locular, 2-valved, dorsal locule 1-seeded, indehiscent, ventral locules 2-seeded. Seeds slightly dimorphic, dark brown with orange-brown verrucae, farinose, farina peach-colored; dorsal locule seed strongly adhered to the capsule wall, ellipsoid, strongly dorsiventrally compressed, ventrally flattened, not cleft towards the embryotega, 3.4-4.2 × 2.8-3.3 mm, testa shallowly foveolate, embryotega semilateral, relatively inconspicuous, without a prominent apicule, hilum linear, ½ the length of the seed; ventral locule seeds free from the capsule wall, ellipsoid, truncate at one end, ventrally flattened, not cleft towards the embryotega, 2.7-3.4 × 2-2.4 mm, testa foveolate, embryotega semilateral, relatively inconspicuous, without a prominent apicule, hilum linear, ½ the length of the seed.

Specimens seen

(paratypes). BRAZIL. Minas Gerais: Araponga, Parque Estadual Serra do Brigadeiro, Fazenda Neblina, 17 February 2005, L.S. Leoni et al. 6112 (RB, UEC); Camanducaia, Monte Verde, Serra da Mantiqueira, 11 December 2001, L.D. Meireles & R. Belinello 775 (HURB, UEC); Delfim Moreira, Fazenda da Onça, trilha de subida para o Pico do Carrasco, 17 March 2011, L.L. Giacomin et al. 1429 (BHCB, RB); Lima Duarte, Parque Estadual do Ibitipoca, Conceição do Ibitipoca, gruta da Cruz, 30 November 2004, E.V.S. Medeiros et al. 364 (RB); loc. cit., gruta do Cruzeiro, 20 January 2005, L.G. Temponi et al. 407 (RB, UEC); loc. cit., gruta do Pião, 18 January 2005, R.C. Forzza et al. 3926 (RB, UEC); loc. cit., gruta do Cruzeiro, 26 January 2010, J.C. Lopes et al. 76 (RB, SPF); Poços de Caldas, Fazenda Campo da Cachoeira, área destinada para a instalação do Jardim Botânico de Poços de Caldas, 12 December 2001, C.N. Fraga & F.M. Fernandez 864 (RB); loc. cit., 12 December 2001, F.M. Fernandez 151 (BHZB, RB). Rio de Janeiro: Nova Friburgo, Morro da Caledônia, 8 June 1977, G. Martinelli 2469 (BA, RB); loc. cit., Reserva Macaé de Cima, cerca de 900 m do Hotel São João, 19 January 1999, L. Anderson et al. 99/15 (UEC); loc. cit., Reserva Macaé de Cima, cerca de 900 m do Hotel São João, 19 January 1999, L. Anderson et al. 99/20 (UEC); loc. cit., Parque Estadual dos Três Picos, Vale dos Deuses, 28 January 2015, M.S. Wängler et al. 1565 (RB); Resende, Parque Nacional do Itatiaia, estrada BR-485, próximo ao km 02, 22 February 2014, L.S.B. Calazans et al. 242 (RB). São Paulo: Itararé, divisa entre as Fazendas Santa Andreia e Prieto, 14 May 1989, C.A.M. Scaramuzza & V.C. Souza 259 (ESA); Ribeirão Grande, Parque Estadual Intervales, 15 April 2003, R.A.G. Viani et al. 79 (ESA).

Etymology.

This species is named after the British botanist Dr. David R. Hunt, in honor of his extensive contribution to Commelinaceae systematics worldwide, especially for his contributions to Tradescantieae and the " Phaeosphaerion group" of Commelina .

Distribution and habitat.

Commelina huntii was collected in moist and shaded nebular forests, generally near water bodies, in the states of Minas Gerais, Rio de Janeiro, and São Paulo, in elevations from 800 to 1,700 m above sea level (Fig. 5 ). In very rare cases it can also be found in open sometimes disturbed areas.

Phenology.

It was found in bloom from November to June and in fruit from December to March, rarely in June.

Conservation status.

Despite the wide EOO (112,904.528 km2), the AOO (40.000 km2) is considerably small, since all known populations are significantly small and fragmented. Following the IUCN recommendations ( IUCN 2001), C. huntii should be considered as Endangered [EN, B2b(ii, iii)c(iv)+C2a(i)] in its overall distribution.

Affinities.

Commelina huntii can be recognized by its white flowers with auriculate medial petal and sparsely papillose ovary and capsule. It is similar to C. rufipes Seub. due to its white flowers and rusty hairs on the leaf-sheaths, but it can be readily distinguished from the latter by its connate spathe base (vs. free base); auriculate medial petal without medial constriction (vs. entire medial petal with medial constriction); light-brown, ellipsoid, dehiscent capsules (vs. pearly-white to silvery, globose, crustaceous capsules); and by its free, ornamented seeds (vs. seeds fused to the capsule septa, forming a dispersal unit, with smooth testa). The gross floral morphology of C. rufipes is much more similar to the C. benghalensis than the one of C. huntii , possessing only the white petals in common.

Commelina huntii is most similar to C. obliqua Vahl due to its oblique leaf blades, connate spathe base, dehiscent capsules, and ventral seeds free with foveolate testa. Despite this, C. huntii can be distinguished from C. obliqua by its densely setose leaf-sheath margins with rusty to rusty brown hairs (vs. leaf-sheath margins long-ciliate with light to medium to dark brown to atro-vinaceous hairs); petals white (vs. blue to light blue to lilac to pale lilac), paired petals broadly rhomboid to rhomboid reniform (vs. broadly ovate to broadly ovate reniform), medial petal cucullate and biauriculate (vs. involute and entire); anthers of the lateral stamens light-yellow to cream with margins tinted vinaceous (vs. completely orange); ovary and capsules sparsely black papillate (vs. smooth); 1-2 capsules per spathe (vs. 5-7); seeds with peach-colored farina (vs. seeds white farinose), and dorsal locule seeds with shallowly foveolate testa (vs. rugose foveolate testa).

Figures

Figure 3. Commelina huntii M. Pell. A habit B open spathe, showing eventual rusty cilia and villous margin C male flower D medial petal, showing auricles E staminode F lateral stamen and medial stamen G gynoecium, showing papillate ovary and trilobate stigma H capsule, showing the black papillae. Line drawings by M. O. O. Pellegrini, based on the holotype.

Figure 4. Commelina huntii M. Pell. A apex of the stem, showing terminal inflorescence B detail of the densely setose leaf sheath margins, with rusty hairs C detail of the inflorescence, showing the fused spathe and developed upper and lower cincinni D detail of a male flower E detail of the medial petal, showing the two auricles F detail of the androecium G dorsal and ventral view of the seed of the dorsal locule H dorsal and ventral view of one of the seeds of the ventral locules. A by L. S. B. Calazans, B, C, E, G, H by M. O. O. Pellegrini, D by M. S. Waengler and F by R. S. Couto.

Figure 5. Distribution map of Commelina huntii M. Pell.