Pleroma (plant)

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Pleroma
Pleroma mutabile
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Myrtales
Family: Melastomataceae
Genus: Pleroma
D.Don[1]
Species

See text.

Synonyms[2]
  • Ancistrodesmus Naudin
  • Antheryta Raf.
  • Diplostegium D.Don
  • Itatiaia Ule
  • Lasiandra DC.
  • Microlepis (DC.) Miq.
  • Svitramia Cham.
  • Tibouchinopsis Markgr.

Pleroma is a genus of flowering plant in the family Melastomataceae, native from Puerto Rico and the Leeward Islands to tropical South America (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru and Venezuela).[2]

Description[edit]

Species of Pleroma are subshrubs, shrubs or trees. Their leaves are almost always opposite and petiolate, rarely sessile. The inflorescence is a terminal panicle or some modification of one. The flowers are perigynous with a bell- or urn-shaped hypanthium (base of the flower), usually externally covered with short, soft hairs (pubescent). There are usually five petals (sometimes four), purple to lilac, rarely white. The flowers have ten stamens (sometimes eight), often of two distinct sizes, with purple or pink anthers. The connective at the base of an anther is modified into a ventral bilobed appendage. The numerous seeds are contained in a dry semiwoody capsule and are spiral in shape, possibly elongated.[3]

Taxonomy[edit]

The genus Pleroma was established by David Don in 1822. He derived the name from Ancient Greek πλήρωμα, pleroma, meaning "fullness", referring to the way the seeds filled the capsule.[4] Although Don used the genus name as a feminine noun, giving specific epithets feminine endings,[4] the Greek word is neuter, and subsequent authors have used neuter endings (e.g. Pleroma heteromallum rather than Don's Pleroma heteromalla).[3]

In 1885, in his treatment for Flora brasiliensis, Alfred Cogniaux used a broad concept of the genus Tibouchina, transferring into it species at that time placed in Pleroma and other genera. This broad concept was generally adopted subsequently, and around 470 taxa were at one time or another assigned to Tibouchina.[3] A phylogenetic analysis in 2013 based on molecular data (2 plastid and 1 nuclear regions) determined that the broad circumscription of Tibouchina was paraphyletic. Four major clades were resolved within the genus which were supported by morphological, molecular and geographic evidence.[5] A further molecular phylogenetic study in 2019 used the same molecular markers but included more species. It reached the same conclusion: the original broadly circumscribed Tibouchina consisted of four monophyletic clades. The authors proposed a split into four genera: a more narrowly circumscribed Tibouchina, two re-established genera Pleroma and Chaetogastra, and a new genus, Andesanthus. The part of their maximum likelihood cladogram which includes former Tibouchina species is as follows,[3] using their genus names and with shading added to show the original broadly circumscribed Tibouchina s.l. (The relationship between Chaetogastra and the genus Brachyotum differed between analyses.)

Tibouchina s.s.

Pleroma

clade 1 (other genera)

clade 2 (other genera)

Pleroma is shown to be sister to Tibouchina.[3]

Species[edit]

As of April 2022, Plants of the World Online accepted the following 162 species:[2]

Distribution and habitat[edit]

Pleroma species are mostly native to eastern Brazil in the Atlantic Forest and Cerrado biomes, more rarely in the Caatinga.[3] A few species reach other parts of South America and the Caribbean (Bolivia, Colombia, Ecuador, French Guiana, the Leeward Islands, Peru, Puerto Rico and Venezuela).[3][2] They are found in forests and forest margins, river banks, high altitude grasslands, rocky outcrops and restingas, from sea level up to an elevation of 2,650 m.[3]

References[edit]

  1. ^ "Pleroma D.Don", The International Plant Names Index, retrieved 2022-05-02
  2. ^ a b c d "Pleroma D.Don", Plants of the World Online, Royal Botanic Gardens, Kew, retrieved 2022-05-02
  3. ^ a b c d e f g h Guimarães, P.J.F.; Michelangeli, F.A.; Sosa, K. & de Santiago Gómez, J. (2019), "Systematics of Tibouchina and allies (Melastomataceae: Melastomateae): A new taxonomic classification", Taxon, 68 (5): 937–1002, doi:10.1002/tax.12151, S2CID 213372275
  4. ^ a b David Don (1823) [16 November 1822]. "XXIV.—An Illustration of the Natural Family of Plants called Melastomaceæ". Memoirs of the Wernerian Natural History Society. IV, part II. Edinburgh: Printed [by P. Neill] for Adam Black, North Bridge, Edinburgh; London: Longman, Hurst, Rees, Orme, & Brown: 295. OCLC 1160053880. Retrieved 2024-03-06. Nomen duxi ab voce Græca πληρωμα, plenitudo, quòd loculi capsulæ placentis carnosis seminiferis farcti sunt. [I took the name from the Greek word πληρωμα, fullness, as the loculi of the capsules are stuffed with fleshy seed-producing cakes.]
  5. ^ Michelangeli, Fabian; Guimaraes, Paulo J.F.; Penneys, Darin S.; Almeda, Frank & Kriebel, Ricardo (2013), "Phylogenetic relationships and distribution of New World Melastomeae (Melastomataceae)", Botanical Journal of the Linnean Society, 171: 38–60, doi:10.1111/j.1095-8339.2012.01295.x