Bromheadia, commonly known as reed orchids, is a genus of approximately 29 species of flowering plants in the family Orchidaceae (order Asparagales). The genus ranges across tropical Asia into northern Australia, growing from Myanmar and Vietnam south to Java and east to New Guinea and the Philippines, with outlying species in Sri Lanka and Queensland.
Plants in the genus are evergreen herbs with a short, creeping rhizome and erect, unbranched stems bearing flattened, leathery leaves arranged in two rows along the upper two-thirds of the stem. Members grow as both terrestrials (rooted in soil) and epiphytes (growing on other plants). The flowers are short-lived and appear singly, in succession, near the ends of the flowering stem — a trait that gives rise to the common name "reed orchids". Blooms are relatively large and resupinate, typically white, creamy yellow, or reddish, with sepals that are narrower but longer than the petals. The distinctive labellum projects forwards and bears three lobes, with the side lobes held erect. Each flower produces two pollinia.
The genus is subdivided into two sections based on leaf shape: section Bromheadia, whose members have dorso-ventrally flattened leaves, and section Aporodes, whose members have laterally flattened leaves. A 1997 phylogenetic study found section Aporodes to be monophyletic but section Bromheadia to be paraphyletic; its authors proposed either merging the sections into one or splitting section Bromheadia into three, but no subsequent taxonomic revision has acted on those proposals.
Etymology
The genus name Bromheadia was coined by John Lindley in 1841, published in Edwards's Botanical Register, to honour Sir Edward Bromhead — a British botanist recognised for his investigations into the natural affinities of plants.
Distribution
Bromheadia species occur from Myanmar and Vietnam southward through the Malay Peninsula to Java, and eastward to New Guinea and the Philippines. A smaller number of species extend westward to Sri Lanka and southward to Queensland, Australia.
Taxonomy Notes
The genus is divided into two sections — section Bromheadia (dorso-ventrally flattened leaves) and section Aporodes (laterally flattened leaves) — which represent distinct morphological groups. A 1997 morphology-based phylogenetic analysis concluded section Aporodes is monophyletic whereas section Bromheadia is paraphyletic; the authors suggested either synonymising the two sections or subdividing section Bromheadia into three monophyletic groups. Neither change has been formally adopted. One species, Bromheadia falcifolia, is insufficiently known because all known herbarium specimens were destroyed during World War II.
