<p><strong><em>Pilostyles maya</em>, a novel species from Mexico and the first cleistogamous species in Apodanthaceae (Cucurbitales)</strong></p>

Abstract

Pilostyles maya (Apodanthaceae), a new Mexican species endemic to the Yucatán Peninsula, is described and illustrated. Ecological, geographical, molecular, and morphological evidence are provided to support the new species status of Pilostyles maya. A molecular phylogenetic analysis based on the mitochondrial matR and nuclear 18S genes recovered P. maya as sister to P. mexicana. It is distinguished from its congeners by having cleistogamous, hermaphroditic flowers, tepals with ciliate margins and specificity on a Bauhinia host. These traits are novel for the genus and family. We propose that P. maya be listed as Critically Endangered due to its small known area of distribution and threats from deforestation in its area of occurrence.

Biogeographical History of the Yucatan Peninsula Endemic Flora (Spermatophyta) from a Phylogenetic Perspective1

“…Pilostyles maya P. Ortega, Gonz.-Martínez & S. Vázquez is the only species in the genus that has hermaphroditic flowers, a condition considered ancestral and rare in Apodanthaceae, where most species are dioecious or monoecious (Azevedo, 2010; Schaefer and Renner, 2011). Additionally, P. maya presents cleistogamous flowers, an autapomorphic character in the genus (Ortega-González et al, 2020). Both characters require low energy expenditure and are deemed reproductive strategies that increase the likelihood of self-pollination (Bawa and Beach, 1981; Cardoso et al, 2018).…”

Reproductive aspects and pollination biology in endoparasiticPilostyles thurberi(Apodanthaceae)

“…In the family Apodanthaceae, almost all species have unisexual flowers and are described as dioecious or monoecious (Kuijt, 1969;Heide-Jørgensen, 2008;Bellot & Renner, 2014a;Pab on-Mora, 2014a), except for P. maya, which is a cleistogamous hermaphroditic species (Ortega-Gonz alez et al, 2020). This taxonomic description of the sexual systems (dioecy or monoecy) corresponds to the assumption that only one individual has infected a host plant.…”

“…is a genus of endoparasitic plants in the family Apodanthaceae. Pilostyles parasitizes the stems of some species of Fabaceae, its flowers are generally unisexual, and the sexual arrangement or organization of their flowers has been called dioecious or monoecious sexual systems (Bellot & Renner, 2014a; Ortega‐González et al, 2020). The genus is distributed globally and 11 species are recognized, but Pilostyles thurberi A.…”

“…Apodanthaceae flowers break the host's bark to emerge and perform sexual reproduction annually (Bellot & Renner, 2014a; González & Pabón‐Mora, 2014a). Floral unisexuality is present in almost all species, except for Pilostyles maya P. Ortega, Gonz.‐Martínez & S. Vázquez, a hermaphrodite and cleistogamous species within the family (Ortega‐González et al, 2020). There are reports of potential pollinators such as ants, bees, beetles, bugs, butterflies, flies, thrips, and wasps (Bellot & Renner, 2013; Blarer et al, 2004; de Azevedo, 2010; Dell & Burbidge, 1981; González & Pabón‐Mora, 2014b; Kummerow, 1962; Sipes et al, 2014).…”

“…The genus is distributed globally and 11 species are recognized, but Pilostyles thurberi A. Gray has the best-documented distribution in the USA and Mexico (Bellot & Renner, 2014a;Gonz alez & Pab on-Mora, 2014a;Ortega-Gonz alez et al, 2020). However, little research has been conducted regarding its reproductive biology.…”