Pseuderanthemum Radlk.

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 : 326

Pseuderanthemum Radlk.

— Pseuderanthemum consists of about 65 species that occur in tropical regions worldwide. Our count of n = 21 for P. graciliflorum (Nees) Ridl. ( Fig. 2C ) is the first for this native of southeastern Asia. The species was treated as conspecific with P. crenulatum Wall. ex Lindl. by Hu et al. (2011), but the taxonomy of Asian/Malesian species of the genus remains to be fully resolved. Plants from which the chromosome count was made differ from the description of P. crenulatum in Hu et al. (2011) by their shorter bracts (2–4 vs. ca. 7 mm long).

At least 10 counts of n = 21 have been made previously for 7 species of Pseuderanthemum from North America, eastern Africa, India, and islands of the southern Pacific Ocean ( De 1966; Kaur 1966; Govindarajan and Subramanian 1985; Daniel 2000a; Daniel and Chuang 1989, 1993, 1998; Daniel et al. 1990, 2000). Thus, a common number would appear to occur from throughout most of the range of the genus; counts of species in South America remain unknown. Although n = 30 was reported for P. laxiflorum Hubb. ex L.H. Bailey by Kaur (1969), n = 21 appears to be widespread both in the genus and among species in related genera of Justicieae : Odontoneminae sensu stricto. (see above under Graptophyllum and Odontonema ). This number may be postulated to be the ancestral basic number for both Pseuderanthemum and Odontoneminae sensu stricto.

Figures

FIGURE 2 (lower right). Chromosomes of Acanthaceae in pollen mother cells. A. Ruellia costaricensis, telophase II, n = 17. B. Strobilan- thes hamiltoniana, telophase I (distance between poles of cell reduced for presentation), n = 11. C. Pseuderanthemum graciliflorum, metaphase I, n = 21. D. Peristrophe speciosa, metaphase I, n = 30. E. Strobilanthes hamiltoni- ana, diakinesis (showing nucleolus, n), n = 11. Chromosomes shown in outline only are touch- ing or overlapping other chromosomes. Scale applies to all figures. See Table 1 for voucher information.