Platanus kerrii

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Platanus kerrii
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Platanaceae
Genus: Platanus
Species:
P. kerrii
Binomial name
Platanus kerrii

Platanus kerrii (Kerr's plane) is a rare and distinctive species of plane tree (sycamore) native to the tropical forests of Vietnam and Laos in Southeast Asia. It is the only extant member of the subgenus Castaneophyllum, representing the most basal lineage within the genus Platanus. Unlike all other plane trees, P. kerrii is evergreen and retains unlobed leaves throughout its adult life, with none developing the lobed form characteristic of other Platanus species. While some have speculated that P. kerrii might represent a living analogue of ancestral plane trees, no fossil material clearly displaying its distinctive morphology (such as it's pollen morphology) has been found. [2] Even it's distinctive leaf form, once thought to reflect a primitive condition linking it to Cretaceous ancestors, is now understood as a derived feature rather than evidence of direct ancestry from early Platanus-like forms. [3]

Contents

Taxonomy

It is placed in its own subgenus Casteneophyllum, and it has been proposed that this species should be separated out into its own genus. [4] The plant is named after Arthur Kerr, who collected the type specimen in Laos in 1932. [5]

Description

Platanus kerrii is native to Laos and Vietnam, where it is called "ma nang" or "chò nước" in Vietnamese. [1] It differs from other species in the genus in being a tropical plant, evergreen, having unlobed leaves, and in the leaf stem not enclosing the axillary bud at its base. The bark flakes off as with other species, and the trunk of a mature tree appears similar to that of the other species. The leaves are elliptical to lanceolate. The fruits are borne in globose heads, each of which is sessile on a long peduncle. There are up to 12 heads on a peduncle. [4]

References

  1. 1 2 World Conservation Monitoring Centre (1998). "Platanus kerrii". The IUCN Red List of Threatened Species . 1998. IUCN: e.T32830A9733710. doi: 10.2305/IUCN.UK.1998.RLTS.T32830A9733710.en . Retrieved 9 January 2018. Listed as Vulnerable (VU A1c v2.3)
  2. Denk, Thomas; Tekleva, Maria V. (September 2006). "Comparative pollen morphology and ultrastructure of Platanus: Implications for phylogeny and evaluation of the fossil record". Grana. 45 (3): 195–221. doi:10.1080/00173130600873901. ISSN   0017-3134.
  3. Baas, P. (October 1969). "Comparative anatomy of Platanus kerrii Gagnep". Botanical Journal of the Linnean Society. 62 (4): 413–421. doi:10.1111/j.1095-8339.1969.tb01975.x.
  4. 1 2 E. A. Wheeler (1995), "Wood of Platanus kerrii", IAWA Journal , 16 (2): 127–132, doi: 10.1163/22941932-90001399
  5. Harvard University Herbarium Specimen Index