Monophyllaea horsfieldii
| Monophyllaea horsfieldii | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Lamiales |
| Family: | Gesneriaceae |
| Genus: | Monophyllaea |
| Species: | M. horsfieldii
|
| Binomial name | |
| Monophyllaea horsfieldii R.Br.
| |
Monophyllaea horsfieldii is a rare species of herbaceous lithophyte in the family Gesneriaceae, known for its unusual morphology. It is native to parts of Southeast Asia, particularly Borneo and Peninsular Malaysia, where it typically grows on shaded limestone outcrops.[1][2]
Description
Unlike most flowering plants, the genus Monophyllaea is monophyllous, producing only a single, gigantic leaf, which gives the genus its name ("mono" meaning one, and "phyllaea" from Greek for leaf). This leaf is actually a cotyledon; the plant does not develop a second leaf after germination, making it an example of a determinate growth system and a botanical curiosity.[3] In M. horsfieldii, this massive lamina can exceed 1 metre (40 in) long and 75 cm (30 in) wide, supported by an elongate hypocotyl of comparable length. Growth occurs from a meristematic zone at the junction between the hypocotyl and the leaf base, while the margins of the leaf gradually senesce and die back.[1][2]
Habitat and Distribution
M. horsfieldii is typically found in humid, shaded microhabitats of karst limestone formations, which offer excellent drainage and stable environmental conditions. The species is endemic to lowland and lower montane tropical forests in Borneo (especially in Sarawak and Sabah) and peninsular Malaysia.[4]
Ecology
As a lithophyte, M. horsfieldii thrives on rocks, extracting moisture and nutrients from accumulated organic matter in rock crevices. Its large photosynthetic surface and slow growth pattern make it well-adapted to stable environments with low competition. Its reproduction is presumed to be dependent on specific pollinators and conditions, although detailed ecological studies are limited.[3]
Taxonomy
Monophyllaea horsfieldii was originally described in the early 19th century and is placed within the subfamily Didymocarpoideae. The genus Monophyllaea is known for its peculiar growth habit, which challenges typical developmental pathways in angiosperms. Recent molecular studies support its placement within the Gesneriaceae and highlight its close relationship with other genera that exhibit unifoliate or anisophyllous growth forms.[5]
Conservation
Due to its restricted habitat, M. horsfieldii may be vulnerable to habitat degradation, particularly limestone quarrying and deforestation in Southeast Asia. However, the species is not currently listed on the IUCN Red List, and comprehensive assessments of its conservation status are lacking.[6]
References
- ^ a b Cranbrook, Earl of (1988). Key Environments - Malaysia. Elmsford, N.Y.: Pergamon Press. p. 62. ISBN 0-08-028866-9.
- ^ a b Graf, Alfred Byrd (1970). Exotica. East Rutherford, N.J.: The Roehrs Company. p. 1655.
- ^ a b Tsukaya, Hirokazu (2002). "Leaf Development in Monophyllaea and Its Significance in Understanding the Evolution of Monophylly". Development, Growth & Differentiation. 44 (3): 207–218. doi:10.1046/j.1440-169X.2002.00627.x.
- ^ Burtt, B. L. (1981). "Studies in the Gesneriaceae of the Old World: XLVII. Revised Generic Concepts for Boea and Monophyllaea". Notes from the Royal Botanic Garden Edinburgh. 39: 467–486.
- ^ Möller, M.; Clark, J. L. (2010). "The State of Molecular Studies in the Family Gesneriaceae: A Review". Selbyana. 31 (2): 95–125.
- ^ "Monophyllaea horsfieldii R.Br". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2025-04-08.