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| Phyllanthus pterocaulis M.J. Silva, in Silva, Alonso & Santos, 2022. |
Abstract
A new species from the state of Goiás, Brazil, Phyllanthus pterocaulis, is described and illustrated, with comments on its geographic distribution and environmental preferences, phenology, morphological relationships, and systematic position. It is morphologically allied with Phyllanthus avicularis, P. heliotropus, and P. hyssopifolioides, but differs from all of them by a set of characters related to cymules sex, presence and types of trichomes on leaves and stems, leaf consistency, numbers of sepals in flower of both sexes, integrity of stamens, capsules and seeds. Additionally, we provide images of the new species in the field, conservation status, mapped distribution, the anatomical description of its stem and leaves, and a key to differentiate it from the other similar species belonging to Phyllanthus sect. Loxopodium occurring in Brazil. The new species is one of the few in the genus that occurs in shaded environments in seasonal dry forests within the Cerrado biome.
Keywords: Seasonal dry forest, Phyllanthus sect. Loxopodium, Phyllantheae, diversity, taxonomy, Eudicots
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| Phyllanthus pterocaulis M.J. Silva. A. Habit; B. Portion of branch, note the winged projections and hispidulous trichomes; C. Stipules; D. Leave, note the ciliate margin; E. Detail of lower side of the leaf blade showing trichomes; F. Detail of the bisexual cymules. G. Staminate flower; H. Pistillate flower in frontal view; I. Pistillate flower, note the disk and ovary; J. Fruit; k. Mericarps removed showing the carpophorous; L. Seed, lateral view; M. Seed, dorsal view. (drawings by Cristiano Gualberto, from the holotype) |
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| Phyllanthus pterocaulis M.J. Silva. A. Habit; B. Portion of branch showing the cymules and fruit; C. Detail of the cymules; D. Staminate flower in frontal view; E. Pistillate flower in lateral view, the sepals green whitish; F. Pistillate flower in upper view, the sepals reddish; G. Fruit; H. Seeds in dorsal and lateral view. Photographs by M. J. Silva. |
Phyllanthus pterocaulis M. J. Silva. sp. nov.
Diagnosis:—This species can be differentiated from its most similar species (see table 1) by having herbaceous habit up to 13 cm tall, stem short and sparsely hispidulous, conspicuously winged in cross section, Leaves ovate with margin irregularly serrate, base truncate or cordate, hispidulous below; flowers on both sexes 5 or 6-merous, the staminate ones with three free stamens, the pistillate ones with bilobed stigma.
Etymology:—The specific epithet “pterocaulis” refers to the cross section of its winged stem (“ptero” from the Greek “pterón”, plus “caulis”, from Latin).
Marcos José da Silva, Alexandre Antônio Alonso and Igor Soares dos Santos. 2022. A New Critically Endangered Species of Stone Breaker (Phyllanthus, Phyllanthaceae) from Central Brazil, with Notes on its Leaf and Stem Anatomy. Phytotaxa. 530(1); 53-64. DOI: 10.11646/phytotaxa.530.1.4
