The Rediscovery of Globba arracanensis (Zingiberaceae) in Myanmar

From Plant Press Vol. 12, no. 4 from 2009

By Michael Bordelon and W. John Kress

Inflorescence of Globba arracanensis (Photo by Leslie Brothers)

In October of 1869 north of Akyab (now called Sittwe) in the Kolodyne River Valley of Arracan (now called Rakhine) State in Myanmar, Wilhelm Silpuz Kurz collected a plant that he would later name Globba arracanensis in the family Zingiberaceae. The plant was reported by Kurz to be widely distributed in the mixed deciduous forests of the low hills of the region. The month of October marks the start of the dry season in the western hills of Myanmar and the plant must have been in the early stages of starting to go dormant when collected by Kurz. Seed was present when he found it.

Only three known voucher specimens of Globba arracanensis were made by Kurz. The holotype is at the Royal Botanic Gardens, Kew; two isotypes are at RBG Kew and the herbarium at the Botanic Garden in Calcutta. Kurz published this new species the year after he found it in 1870 in the Journal of the Asiatic Society of Bengal (vol. 39, page 83-84). Globba arracanensis, in subgenus Mantisia section Haplanthera, is the least studied and least understood species in the entire genus and is closely related to G. andersonii from the Darjeeling region of India.

This species was not collected again in Myanmar or any other country for 135 years and was presumed to be extinct. However, we discovered it again during a collecting expedition to Myanmar in mid-November 2004, 32 miles north of Sittwe along the road to Mrauk U, just north of Ponnagyun in Rakhine State. At that time the plant was completely dormant and the foliage was dry and unrecognizable. The rhizome was attached to a large boulder in a dry stream bed in the understory of a bamboo forest. We were collecting any gingers that we found, even if dormant. Until this collection Globba arracanensis was only known from the type specimen. We knew at the time we collected it that we were in the area visited by Kurz in1869, but we did not know we had re-found this species until our plants flowered sixth months later in our greenhouses.

The rhizomes that we collected in Myanmar were brought back to the Smithsonian Institution’s Department of Botany Research Greenhouses in Washington, D.C. The rhizomes were potted up and allowed to complete their dormancy cycle. In May of the next year (and each year after that) the plants broke dormancy and flowered; in 2008, they finally set seed, either due to natural visitation by bumble bees in the greenhouses or as a result of hand-pollination by one of us.

Close-up of flower of Globba arracanensis (Photo by Leslie Brothers)

The plants of Globba arracanensis are deciduous with stems to 60 cm, arching and curving upward. Leaves are green up to 8 cm wide and 28 cm long, ovate-elliptic tapering to a thread-like tip. The inflorescence is terminal on the leafy shoots. Inflorescence bracts are persistent, starting green then maturing to a pale white, while the bracteoles are persistent and light lilac. The flared almost petal-like lateral staminodes of the flowers are white to light lilac while the labellum is bifid, yellow and lilac with yellow tips, one crossing over the other. The petals are white to light lilac, the floral tube is white, the filament white, and the anther light lilac with a darker almost purple tip. The pollen is white. The fruits are pale green and the seeds are tan and pubescent with an aril. The plants do not produce bulbils in the axils of the inflorescence bracts. According to Kurz’s description the bracteoles, petals, lateral staminodes and filament were lilac in the plants he found. However, natural variation in color is quite common in globbas (especially in species with white and purple flowers) and we suspect that our plants represent such natural variability from the type collection.

Although Globba arracanensis is now known not to be extinct in its native habitat, the rapid degradation of the forests and natural habitats of Rakhine State suggest that measures should be sought to insure the conservation of this and other species under threat in the region.