Pachycentria glauca

The species is a small shrub, epiphytic, with many hanging, creeping or erect branches and adventitious roots that have irregular, globose swellings up to 2 cm in diameter.^[2] These swellings have the same anatomical structure as a storage root. The round branchlets have minute scales, with the older branches are stunted and have thickened node, the globose swellings. Leaves are elliptic-lanceolate or obovate-suborbicular with a cuneate base and an apex that can be truncate, rounded or acute, often red below, some 1.4 to 4 cm by 0.5 to 2 cm in size. The terminal or axillary inflorescences have solitary or pairs of flowers. Flowers have white to pink petals. Anthers are slender and have a long thin, curved upward tip, the style points downward. Septae disappear in young buds. The young berries are urceolate (urn/pitcher-shaped), but become globose, about 5mm in diameter, when immature they are green with a reddish rim, and become red on ripening. There are 5-10 cylindrical seeds some 2 to 2.5mm long (relatively large for the genus), with smooth testa cells.

The species is distinguished by the following characteristics: the terminal or axillary inflorescences with 1 or 2 flowers; the 5-10 cylindrical seeds about 2-2.5mm long; an anther appendage of a thick, dorsal, smooth margin spur; the size of the leaves (1.5-4 x 0.5-2 cm); adventitious roots which often have globose swellings; the flowers are mostly axillary, paired or solitary in simple cymes; the species often grows on ant plants.^[2]

The leaves of P. glauca subsp. glauca grow small, 1-nerved, elliptic to lanceolate leaves (only 2-4 by 0.5-2 cm) when growing on ant-plants, in the wild. However when grown under greenhouse conditions, the leaves are longer, broader, ovate and have 3 nerves. This is an example of the large phenotypic variation of leaves in the Pachycentria genus.^[2]

The autonym P. glauca subsp. glauca has elliptic-lanceolate leaves with an acute apex.

The maingayi subspecies has leaves that are obovate-suborbicular with a truncate or rounded apex.^[2] In Thailand flowering and fruiting occurs from April to October.^[3]

This species has two accepted subspecies:^[4]

• Pachycentria glauca subsp. glauca
• Pachycentria glauca subsp. maingayi (C.B.Clarke) Clausing

The species was named by the Colombian botanist José Jerónimo Triana (1828–90), who also produced medical products and how-to-read books. He published his description in an edition of Transactions of the Linnean Society of London produced in 1871 but published in 1872.^[5]

The maingayi subspecies was named in 2000 by the botanist Gudrun Clausing (born 1969) who was working at Johannes Gutenberg-Universität Mainz.^[6][7][2] The description was published in the journal Blumea. The subspecies was based on the previous taxa Medinilla maingayi, described by the English botanist Charles Baron Clarke (1832-1906) in 1879, in the publication The Flora of British India overseen by Joseph Dalton Hooker.