Pilea

Abstract: Veloporphyrellus is a genus known from North and Central America, southeastern Asia, and Africa. Because species of this genus are phenotypi- cally similar to some taxa in several genera, such as Boletellus, Leccinum, Strobilomyces, Suillus and Tylopi- lus s.l. belonging to Boletales, its phylogenetic disposition has never been addressed. We analyzed four DNA regions, the nuclear ribosomal LSU and tef- 1a, and the mitochondrial mtSSU and atp6 genes, to investigate the phylogenetic disposition of Velopor- phyrellus. Although the monophyly of the genus and its systematic placement within the Boletaceae was well supported, its relationship to other genera was not resolved. Morphologically Veloporphyrellus is distinguished from other boletoid genera by the combination of the pinkish or grayish pink hymeno- phore, the membranous veil hanging on the pilea margin, the trichoderm-like pileus covering and the smooth basidiospores. Five species, including two new species and two new combinations, are described and illustrated. A key to the species of Veloporphyrellus also is provided.

Abstract: During the course of floristic studies on Urticaceae in Distrito Federal, Brazil, we encountered a species of Pilea that was not described until now. Pilea brasiliensis is here described and illustrated, its affinities are discussed and its position in Weddell & Killip’s subdivisions of the genus is indicated. A Conservation Assessment determines P. brasiliensis to be Critically Endagered (CE) with the possibility that it may be Extinct in the Wild (EW).

Abstract: Pilea peperomioides Diels (Urticaceae) is a semi-succulent herbaceous species native to south-western China that has become popular in cultivation as an ornamental plant. To investigate whether this species possesses the capacity for CAM photosynthesis, measurements were made of CO2 gas exchange and titratable acidity in plants under both well-watered and water-deficit conditions. Plants were found to assimilate CO2 almost exclusively in the light via C3 photosynthesis. However, distinct transient reductions in the rate of net nocturnal CO2 release were consistently observed during the course of the dark period, and under water-deficit conditions one plant exhibited a brief period of net nocturnal CO2 uptake, providing unequivocal evidence of CAM activity. Furthermore, nocturnal increases in titratable acidity in both leaf laminas and petioles were observed in all plants exposed to wet-dry-wet cycles. This is the first report of CAM in the family Urticaceae. The results are discussed in relation to the phylogenetic position of Pilea and the partially shaded montane habitats in which this species is typically found. An updated list of all plant families currently known to contain species with CAM is presented.

Abstract: Three hitherto undescribed species of Pilea (Urticaceae) from limestone karst in China are described and illustrated. Affinities of the species are discussed and Global Species Conservation Assessments presented. The new species are Pilea cavernicola A.K. Monro, C.J. Chen & Y.G. Wei, sp. nov. (Vulnerable) which most closely resembles Pilea scripta (Buch.-Ham. ex D.Don) Wedd. and Pilea gracilis Handel-Mazzetti, Pilea shizongensis A.K. Monro, C.J. Chen & Y.G. Wei, sp. nov. (Endangered) which is most similar to Pilea aquarum Dunn and Pilea guizhouensis A.K. Monro, C.J. Chen & Y.G. Wei, sp. nov. (Vulnerable) which resembles Pilea boniana Gagnep. and Pilea rubriflora C. Wright mostclosely.