Portulaca amilis Speg.

Coelho, A.A.O.P., Giulietti, A.M., Harley, R.M. et al. (2010). Synonymies and typifications in Portulaca (Portulacaceae) of Brazil. Kew Bulletin 65: 37. https://doi.org/10.1007/s12225-010-9187-2

Type

Paraguai, Assuncion, Oct 1919, Spegazzini s.n. (holotype MVM!).

Morphology General Habit

Portulaca amilis is well characterised by the prostrate habit, and the stem with transversal striations, that occur only in this species

Morphology General

It has oblong-lanceolate leaves, 5 – 15 (– 20) × 1 – 2 mm, leaf venation with evident midrib, rounded base, acute to acuminate apex; pyxidium 4 – 5 mm long, dehiscence at the middle of the capsule or above it, peduncle c. 1 mm long; seeds 15 – 20 per fruit, black, opaque, 1 – 2 × 0.3 – 0.8 mm; verrucose, with small conical tubercles.

Distribution

The species occurs only in South America from Peru to Brazil, Bolivia, Paraguay and Argentina. In Brazil, from the state of Pará to Mato Grosso do Sul in savanna areas and from Rio de Janeiro to Santa Catarina in coastal dune ecosystems.

Note

Legrand (1962) described Portulaca amilis var. minensis and P. amilis var. pilgeri based only on the differences in leaf size and seed diameter. P. amilis var. minensis varies between 18 – 20 mm in leaf length and up to 0.56 mm in seed diameter, while P. amilis var. pilgeri has leaves up to 15 mm and seeds with more than 0.56 mm diam. Material studied from different habitats showed a continuous variation in leaf size up to 20 mm and in seed diameter to 0.8 mm. For these reasons, both varieties were synonymised under Portulaca amilis Speg. As the species has a large distribution, some variation occurs related to leaf size and seed diameter. For example: the leaf length recorded for specimens collected in the savanna areas from Mato Grosso [Hatschbach 21972 (MBM!)], Mato Grosso do Sul [Pott 1396 (MBM!)] and São Paulo [Magenta et al. 222 (HRCB!)] varied between 10 – 20 mm in length. However, plants from the dune ecosystem possessed leaves varying from 5 – 10 mm long. Portulaca striata was described by Poellnitz (1934) based on Schenck 1055 from the coast of Santa Catarina state. According to the protologue, this species was distinguished by its stem striation. The analysis of many specimens from Rio de Janeiro down to Santa Catarina state show that plants of dunes present the smallest size of leaves but all characteristics, especially the striation on the stem are typical for P. amilis. Portulaca glazioviana was described by Legrand (1953) from a specimen collected in coastal dune vegetation in Rio de Janeiro. According to the author, the species is characterised by the capsule dehiscence (at the middle portion of the capsule or above it). The author also mentioned that P. glazioviana is similar to P. mucronata Link. in having the same leaf outline (oblong-lanceolate) and by the characteristics of the seed (seeds almost smooth). However, by studying the type material, it was concluded that this species shares all the characteristics of P. amilis including the seed sculpture and striation on the stem, which is a distinct feature found only in this species.