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. 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. …

The autonym subspecies, P. glauca subsp. glauca is endemic to Borneo. The maingayi subspecies is native, to Peninsular Malaysia. There is a single recording of it occurring on the adjacent north coast of Sumatera. In 2009, the subspecies was identified growing in the Sankalakhiri Range of extreme south Thailand.

The species is pollinated by bees, using buzz pollination, using vibrations to collect the pollen. One flower in an inflorescence opens per day, the open flower has stamens bent to one side of the flower, their tips arrange in close proximity with the style remaining either in the middle or pointing to the other side. The bee vibrates and pollen comes from the pores of the anthers. After pollination the petals reflex and stamens spread. The fruit are dispersed by small to mid-sized birds and ants disperse seeds. The ants (Philidris and Crematogaster species and Camponotus (Myrmotarsus) irritabilis) take seeds from bird poo or from the ripe fruit. Seedlings are observed on ant plants and in ant gardens. Not only the seeds are attractive to ants, the plant grows pearl bodies as well.

Subspecies glauca is found in kerangas, dry hill and old secondary forest from sea level to 1100m elevation. It grows as an epiphyte very frequently (perhaps exclusively) on ant plants, especially on other epiphytes such as Hydnophytum, Myrmecodia and Lecanopteris. The root swellings of the plant has been observed to be inhabited by ants.

The maingayi subspecies is found in primary lowland, kerangas and heath forests at the same elevation ranges as its sibling subspecies. …