Whitfieldia Hook.

Daniel, Thomas F., 2018, Chromosome Numbers of Some Cultivated Acanthaceae with Notes on Chromosomal Evolution in the Family, Proceedings of the California Academy of Sciences 64 (9), pp. 319-332 : 328

Whitfieldia Hook.

— Whitfieldia consists of 12 species restricted in distribution to tropical Africa. Our approximate count of n = ca. 21 for W. elongata (P. Beauv.) De Wild. & T. Durand , a widespread species in tropical Africa, is the first for a species in the genus. Chromosomes of Whitfieldia are unusual among those we’ve observed among Acanthaceae in that they are heterochromatic. Most or all of the bivalents exhibit both darkly and lightly stained areas. Depending on interpretation of the preparations, cells showed 20, 21, or 22 bivalents at metaphase I of meiosis.

Manktelow et al. (2001) treated the genus in tribe Whitfieldieae along with two other genera that yielded the following phylogenetic relationship: Lankesteria + ( Chlamydacanthus + Whitfieldia ). These genera were shown to form a well-supported monophyletic group sister to Barlerieae. McDade et al. (2008) confirmed and refined composition and relationships both of and within the tribe; they added three Malagasy genera to Whitfieldieae , and the tribe was treated as sister to Barlerieae + Andrographidieae. Tripp et al. (2013) revealed Zygoruellia Baill. to pertain to Whitfieldieae , as well. No chromosome number has been reported previously for Whitfieldia , and the only number reported to date in the tribe is an older count of n = 25 for Lankesteria elegans T. Anders. (Mangenot and Mangenot 1962). Given the dearth of chromosome numbers for this tribe of seven genera and 31 species (Daniel unpublished data), it seems premature to postulate a basic number for it.