Two peculiar new species of Heteranthera Ruiz & Pavón (Pontederiaceae) from Brazil, with notes on inflorescence architecture in the family

By

Pellegrini, Marco
Horn, Charles

Type

Article

Date of Publication

2017

Original Publication

PhytoKeys

Volume

82

Pages

35-56

Subjects

aquatic flora , Atlantic forest , Commelinales , mudplantains , neotropical flora , pickerelweed

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers [2010]-

Identifiers

DOI: https://doi.org/10.3897/phytokeys.82.13752

 

Abstract

Two new and peculiar species of Heteranthera are herein described. Heteranthera catharinensis is unique in the genus due to its glomerulate, many-flowered inflorescences, in which the flowers are restricted to the base and apex of the cincinni. It also possesses the biggest flowers in the H. reniformis Ruiz & Pavón species complex, with glabrous perianth lobes, medial filament, and style. On the other hand, Heteranthera pumila is described as the smallest known species of Pontederiaceae, with its dwarf stature, petiolate leaves with especially diminute blades, inflorescences 1–2–(3)-flowered, peduncle densely covered with glandular hairs, basal bract with glandular hairs at base, and smooth seeds, rarely possessing 7–9 inconspicuous longitudinal wings. We present detailed descriptions, illustrations, comments, a distribution map, conservation assessments for the new species, and an identification key to the Brazilian species of Heterantheras.l. Finally, we discuss inflorescence morphology and terminology in Pontederiaceae, characterizing it as thyrsoid.