Portulaca hirsutissima Cambèsseds (1829: 191)

Santos, Thaíla Vieira A., Paes Coelho, Alexa Araújo De O., Dórea, Marcos Da Costa, Dos Santos, Francisco De Assis R., Leite, Kelly Regina B. & Oliveira, Reyjane Patrícia, 2016, Micromorphological features revealing two new species of Portulaca (Portulacaceae) from Brazil, segregated from P. hirsutissima, Phytotaxa 270 (2), pp. 103-115 : 111-113

Portulaca hirsutissima Cambèsseds (1829: 191) .

Type (lectotype here designated):— BRAZIL. Minas Gerais: without locality, 1816–1821, Saint-Hilaire s.n. (P-00835689). Image of the lectotype available at https://science.mnhn.fr/institution/mnhn/collection/p/item/p00835689?listIndex=10&listCount=3384. Isolectotypes at P-00835688! (https://science.mnhn.fr/institution/mnhn/collection/p/item/p00835688?listIndex=9&listCount=3384), P-00835687! (https://science.mnhn.fr/institution/mnhn/collection/p/item/p00835687?listIndex=8&listCount=3384), P-00835686! (https://science.mnhn.fr/institution/mnhn/collection/p/item/p00835686?listIndex=7&listCount=3384), MPU010812! (https:// science.mnhn.fr/institution/um2/collection/mpu/item/mpu010812).

Description: —Herb succulent (therophyte), prostrate (rarely erect), 7.0 − 30 cm tall, stems branched, green to purplish; axillary trichomes overlying the entire stem, abundant and conspicuous, whitish, wooly. Leaves sessile, leaf blades 0.5 − 2 cm × 1.5 − 4.0 mm, oblong-linear, adaxial surface flat, the abaxial convex, midrib not evident, base rounded, apex acute, sometimes purplish, margin entire, trichomes covering all surfaces. Inflorescence a terminal capitulum, 4 − 7-flowered, the flowers open one at a time. Flowers sessile, sepals 0.5 − 0.8 cm long, with hirsute trichomes along the margins and abaxial surface, concave, apex acute; petals 5, obcordate, apex emarginate, yellow; style and filaments yellow; similar to the petals coloration, stamens numerous, anther yellow; pollen grains pantoporate, with pores isolated and organized in a polyhedral shape, exine spiny with annulate perforations. Fruit capsule sessile, 2.0 − 3.0 × 1.5–3.0 mm, base conical, 0.2 − 1.0 mm length; operculum ovoid 1.5 − 3.5 × 1.0– 2.5 mm; seeds reniform, more than 100 per fruit, 0.2 − 0.4 mm length, black, seeds covered by grayish and smooth wax throughout the relief, the outline irregular or corrugated in “U”, not bifurcated, the cells without convex projections.

Typification: — Portulaca hirsutissima was described by Cambessèdes (1829) who reported “in pascuis prope Bom Fim et Nossa Sñra da Penha (Minas Novas), necnon prope Tejuco (Certao). Ab indefesso Laruotte lecta”. Coelho et al. (2010) cited as the holotype of this species a specimen preserved at P indicating “Laruotte s.n.”. However, Laruotte was his colleague during the fieldtrips in Brazil, and no material was assigned to him, getting all the samples under Saint Hilaire´s responsibility.

We found at MPU (barcode 010812) and P (barcodes 00835686, 00835687, 00835688 and 00835689) five specimens collected in Minas Gerais during Saint Hilaire´s fieldtrips (1816–1821) bearing labels with original annotations: “Penha”, “Bonfim” and “Tejuco”. Three specimens (P-00835686, P-00835687, P-00835688) bear the annotation “ syntypes ” (by A. Coelho in September 2005), while the P-00835689 was labeled as “ lectotype ”.According to McNeill et al. (2012) any syntype was listed in the protologue, while Coelho et al. (2010) never formalized a lectotypification. According to the Art. 9.9 of ICN ( McNeill et al. 2012), we here correct the Coelho’s statement and designated the specimen P-00835689 as the lectotype for the name Portulaca hirsutissima . We also consider as isolectotypes the other specimens from P and MPU previosly cited by these authors as syntypes.

Taxonomical notes: — Portulaca hirsutissima ( Fig. 1G–H ) it was traditionally considered as a very polymorphic species. Coelho & Giulietti (2010) reported the corolla magenta and/or yellow in specimens of P. hirsutissima from Bahia, and corolla exclusively yellow to specimens from Minas Gerais and other states ( Fig. 1H ). On the basis of the results obtained in the present paper, P. hirsutissima shows pantoporate pollen grains, such pores are isolated and organized in a polyhedral shape ( Fig. 4E ). In addition, the seeds ( Fig. 4F ) display the cells relief covered by a smooth wax deposition, and the outline is irregular or corrugated in “U” shape, not bifurcated and with convex projections ( Fig. 5 ).

Distribution, habitat and conservation: —Samples of Rio de Janeiro, Espírito Santo, Bahia and Paraíba are to be referred to P. giuliettiae (pollen pantocolpate, seeds without convex projections), while those from Goiás, to P. goiasensis (with pollen grains with colpes spirally arranged and convex projections with wax only at the base). The specimens from the type collection, from Minas Gerais, and other samples with a similar micromorphology are identifiable as the actual Portulaca hirsutissima . Preferential habitat is cerrado environments, on rocky and sandy soild. This species is considered as VU (Vulnerable) B1b (ii, iii, iv), with an EOO of about 20000 km 2 according to the IUCN criteria ( IUCN 2012). It is restricted to Minas Gerais State, being directly affected by deforestation in that region.

Specimens examined: — BRAZIL. Minas Gerais: Diamantina, 11 March 2015, Cardoso et al. 3784, 3788 (HUEFS), Serra do Cipó, 5 February 2009, Zappi et al. 1713 (RB). Nova Belém, 22 April 2013, Oliveira 350 (RB).

Figures

FIGURE 1. Morphological features of individuals previously identified as Portulaca hirsutissima. A. Abundant hairs in the leaf axils (Vieira et al. 147). B. Hirsute trichomes covering all surfaces of leaves (Vieira et al. 150). C‒E. Species collected in Bahia (Vieira et al. 150). F. Species collected in Goiás (Zannate 1093). G‒H. Species collected in Minas Gerais (Cardoso et al. 3784).

FIGURE 4. Micromorphological characters of pollen grains and seeds. A‒C. P. giuliettiae (Carneiro-Torres 123). D‒F. P. goiasensis (Pastore et al. 1788). G‒I. P. hirsutissima (Cardoso et al. 3784). Bar = 10μm, except B, E, H bar = 100μm

FIGURE 5. Distribution map of Portulaca hirsutissima and related species in Brazil.