Agatea
Genus of flowering plants in Eudicot family Violaceae
From Wikipedia, the free encyclopedia
Agatea is a genus of flowering plants in the violet family Violaceae, with seven accepted species, found in New Guinea and New Caledonia.
| Agatea | |
|---|---|
| |
| Agatea violaris | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Violaceae |
| Subfamily: | Violoideae |
| Tribe: | Violeae |
| Genus: | Agatea A.Gray[1][2][3] |
| Type species | |
| Agatea violaris A.Gray[4] | |
| Species | |
| |
| Synonyms[2] | |
Description
Lianas or reclining shrubs with lanceolate to ovate leaves. The flowers are in terminal pseudo-racemes or racemoids, with white corollas that are strongly zygomorphic (bilaterally symmetrical) with the very large bottom petal differentiated into a claw and blade and saccate (pouch like) at the base. On the five stamens, the filaments are weakly connate with the two lowest anthers weakly calcarate (spurred) and possessing a large dorsal connective appendage that is entire and oblong-ovate. In the gynoecium, the style is filiform (threadlike) to clavate (club like). The fruit is a thin to thick-walled capsule with 3 or 6 valves. There are two seeds per carpel, that are strongly flattened and encircled with a broad thin wing. The chromosome number is 2n=16.[5][6][7]
Taxonomy
The genus Agatea was first described by Gray in 1852,[8] following the United States Exploring Expedition of 1838–1842, and therefore bears his name, A.Gray, as the botanical authority.[4] Gray's description was of the single species, Agatea violaris, which is thus the type species. His report was published in full in 1854.[9]
Early taxonomic schemes such as Bentham and Hooker (1862)[10] placed Agatea within subfamily Violoideae, tribe Violeae, subtribe Violinae.[6][11] For a while, the name Agatea was disputed, and Agation used instead, but this was resolved in favor of the former name.[12] The genus has also been subject to over-description resulting from polymorphism.
Agatea is one of four lianescent genera in Violaceae, together with Calyptrion Ging., Anchietea A.St.-Hil. and the more recently discovered (2003) Hybanthopsis Paula-Souza.[13] In earlier classifications primarily based on floral morphology these were distributed among separate subtribes, but molecular phylogenetic studies has now grouped them together into a single lianescent clade, one of four within the family. Earlier schemes had placed Agatea within subfamily Violoideae, tribe Violeae, subtribe Hybanthinae, with Hybanthopsis but Calyptrion and Anchietea in subtribe Violinae.[5][11]
Etymology
The genus is named for the botanical draughtsman on the expedition, Alfred T. Agate.[8]
Species
Although estimates of the number of species has varied between one[12] and ten,[7] there are seven[14] or eight[2] generally-accepted species.
- Agatea lecointei Munzinger[12]
- Agatea longipedicellata (Baker f.) Guillaumin & Thorne[15]
- Agatea macrobotrys K.Schum. & Lauterb.
- Agatea pancheri (Brongn.) K.Schum. ex Melch.[12][7][15][1]
- Agatea rufotomentosa (Baker f.) Munzinger
- Agatea schlechteri Melch.
- Agatea veillonii Munzinger[12][15]
- Agatea violaris A.Gray Type
New species, e.g. A. lecointei and A. veillonii, continue to be discovered, these two in New Caledonia in 2001.[12]