Today’s photographs are courtesy of Dr. Marcelo Trovó, a plant systematist in the Instituto de Biociências at the Universidade de São Paulo in Brazil. I became aware of this species after browsing through the latest issue of Systematic Botany where Dr. Trovó and a colleague, Paulo Sano, published a paper entitled, “Five New and Narrowly Distributed Species of Paepalanthus Section Diphyomene (Eriocaulaceae) from Central Brazil” (Systematic Botany (2011), 36(3):610-620, doi: 10.1600/036364411X583600).
Eriocaulaceae is typically a pantropical family, though some representatives grow in temperate areas. Of the 1200 or so species in the family, approximately 550 are in Paepalanthus, making it the most biodiverse extant group. I tried to sleuth the meaning of the name Paepalanthus, and while -anthus is easy (“flower”), Paepal- is not so readily found in my available resources. Assuming that the name comes from the Greek word Paipale as some suggest, then I think Paepalanthus means “meal-flowered” or “particle-flowered” (Paipale is somehow related to pollen and flour meal). For the etymology of the epithet of today’s species, stellatus, I’ll simply quote Trovó’s paper “…refers to the numerous white capitula arranged in an umbellate inflorescence, resembling a star-like constellation”.
Paepalanthus stellatus is found only in open savannas dominated by grass in small areas of Goiás. As photographed here, it can be found in dense populations of over 100 individuals, but as it is known from very few locations in a small geographic area, it can be considered critically endangered according to IUCN Red List criteria.
Growing to 85cm tall, from the basal rosette of leaves (typically persistent) emerges a reproductive axis. At the top of the axis, anywhere from 40-400+ scapes from 13-25cm long emerge, each tipped with an obconic capitulum. The capitula each contain approximately 55 flowers (about 50 of these pollen-producing, and 5 pistillate). The staminate, or pollen-producing, flowers are mature in March, while pistillate flowers reach full maturity in April.