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Rotheca | |
---|---|
Rotheca myricoides | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Lamiales |
Family: | Lamiaceae |
Subfamily: | Ajugoideae |
Genus: | Rotheca Rafinesque |
Type species | |
Rotheca serrata | |
Species | |
See text | |
Synonyms | |
Cyclonema Hochst. |
Rotheca is a genus of flowering plants in the family Lamiaceae.[1] Estimates of the number of species in the genus vary from about 35 [2] to as many as 60.[1] Three of the species are native to tropical Asia, with the rest occurring in Sub-Saharan Africa.[2] The type species for the genus is Rotheca serrata. It had originally been named Rotheca ternifolia, but this name is now considered illegitimate.[3]
Rotheca myricoides is native to tropical East Africa and is cultivated as an ornamental throughout the tropics.[4] Rotheca serrata is from tropical Asia and has some medicinal use there.[2]
In the 20th century, Rotheca was rarely recognized as separate from Clerodendrum. Rotheca was revived in 1998 as a result of phylogenetic analysis of DNA sequences. It can easily be distinguished from Clerodendrum by a combination of morphological characters.[3]
The following description is adapted from the most recent monograph on Lamiaceae.[1]
Rotheca is a genus of shrubs, subshrubs, and herbaceous perennial plants, with a few becoming lianas or small trees. They emit an unpleasant odor when damaged. The leaves are opposite or whorled, and sessile or with a short petiole. The calyx is actinomorphic or nearly so, and not accrescent as in some related genera. The corolla is blue, purple, or white, (rarely yellow), and 5-lobed. The abaxial lobe is often larger and different in color. The four stamens are long-exserted. The ovary is unlobed at anthesis, becoming lobed during maturity. The fruit is 4-lobed and resembles a drupe, but eventually separates into four 1-seeded mericarps.
Rotheca was named by Rafinesque in 1838.[5] The name is a Latinization of a Malayalam name meaning "small teak".[3] The Indian (Malayalam) name has had widely variant spellings.
In 1895, John Isaac Briquet included Rotheca in his rather broad circumscription of Clerodendrum.[6] Briquet's treatment was generally followed for the next 100 years, but doubts about it were often expressed.[7] The genus Rotheca was revived in 1998, based on molecular phylogenetic work, some of which was not published until 1999.[8] In this work, it was shown that inclusion of Rotheca in Clerodendrum renders the latter polyphyletic.
One commonly consulted species list provides only a few examples.[9] The transfer of species from Clerodendrum to Rotheca continues in a piecemeal fashion, and is mostly for the compilation of local floras.[10] As of July 2015[update], The Plant List accepts the following species:[11]