<I>Piresia palmula</I>: a New Species of Herbaceous Bamboo (Poaceae, Olyreae) Endemic to the Atlantic Rainforest, Southern Bahia, Brazil

Abstract

Piresia is a low growing perennial grass in the tribe Olyreae (Poaceae, Bambusoideae). It differs from other herbaceous bamboos in having dimorphic culms: aerial ones bear broad and flat leaf blades at the top and rarely develop an inflorescence, and decumbent ones usually bear reduced leaves or bladeless leaf sheaths, with inflorescences that are raceme-like, few-flowered, and often hidden under the litter. Four species are accepted in this genus, and a fifth one is described and illustrated herein. Piresia palmula. This new species resembles P. leptophylla in having narrow leaf blades, but differs in the number of aerial culms, texture of leaf blades, and in the number and size of inflorescences on both aerial and decumbent culms. Both species are associated with rainforest remnants, but display distinct patterns of geographic distribution and environmental conditions. Piresia leptophylla occurs in northern South America and northeastern Brazil (Bahia to Parai'ba), often in sandy soils, especially in "Restinga" forests, whereas the new species is known only from Michelin's Ecological Reserve, in southern Bahia, growing on rocky substrate in a humid environment. For these reasons it is considered as CR (critically endangered) according to IUCN criteria.

Phylogenetics of Piresia (Poaceae: Bambusoideae) reveals unexpected generic relationships within Olyreae with taxonomic and biogeographic implications

“…The characters selected from these materials were based on the literature (Swallen, 1964; Soderstrom, 1982; Clayton & Renvoize, 1986; Judziewicz & al., 1999; R.P. Oliveira, 2001; Carvalho & al., 2012, 2020; Lima & al., 2020, 2021) and online databases (http://www.tropicos.org; http://www.ipni.org; http://www.kew.org/wcsp; http://www.kew.org/data/grasses-db.html). These collections were also used for updating descriptions, habitat preferences and the geographical distribution of the analyzed taxa.…”

“…Carvalho (2013), however, provided evidence for the existence of additional, potentially cryptic and as yet undescribed species in this genus. Piresia is usually distinguished from the other genera of Olyrinae by the following combination of field characters: two types of culms, leafy ones, which are more numerous and bear many leaves toward the apex, producing a crowded pinnate‐to‐palmate‐appearing leaf complement, and reduced‐leafy ones (sensu Judziewicz & al., 1999), which grow decumbently, hidden under the litter, and bear reduced or vestigial leaf blades and single racemose synflorescences (these sometimes also present in the leafy ones); each raceme with a terminal female spikelet subtended by 2 to several male spikelets; and female floret with dark spots at maturity (Swallen, 1964; Soderstrom, 1982; Clayton & Renvoize, 1986; Judziewicz & al., 1999; Clayton & al., 2006–; Carvalho & al., 2012, 2020).…”

“…(1999), Piresia grows in wet lowland (less than 300 m) forest understories from Colombia, Venezuela, Trinidad, and the Guianas to Amazonian Ecuador, Peru, Bolivia and Brazil, often in periodically flooded sites (“várzea”) in Amazonia or in sandy “mata litorânea” on the Atlantic coast. Thus, this genus has a peculiar disjunct geographical distribution between the Caribbean and north/western South America and the northeastern Atlantic Forest in Brazil (Soderstrom & Calderón, 1974; Judziewicz & al., 1999) with no species shared between the two regions (Carvalho & al., 2012, 2020; Carvalho, 2013).…”

Análise estrutural e micromorfológica da lâmina foliar de populações de Guadua Kunth (Poaceae: Bambusoideae: Guaduinae) ocorrentes no Brasil

“…O Brasil é um dos países com a maior riqueza de bambus no mundo, e a maior da diversidade no hemisfério ocidental CLARK, 1990; 2012;CARVALHO et al, 2012;FERREIRA et al, 2013b;MOTA et al, 2014;FERREIRA et al, 2016).…”