Peristrophe Nees.

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 : 325

Peristrophe Nees.

— Peristrophe consists of about 45 species that occur in Africa, Madagascar, Asia, Malesia, and possibly Australia (cf. Barker 1996). The genus pertains to Justicieae : Diclipterinae. Some evidence suggests that the genus could be treated as conspecific with Dicliptera Juss. (see discussion in Kiel et al. 2017), and phylogenetic analyses based on molecular data reveal that the genus is not monophyletic as currently circumscribed ( Kiel et al. 2017). Our count of n = 30 for P. speciosa (Roxb.) Nees ( Fig. 2D ), a species of the Indian Subcontinent ( Bhutan, India, Nepal), agrees with the previous count for this species by Sareen and Sanjogta (1976). A report of n = 15 for P. speciosa ( Vasudevan 1976) suggests euploidy (presumably diploid and tetraploid occurrences) in this species. Elsewhere in the genus, n = 15 has been reported for P. paniculata (Forssk.) Brummitt (see summary of at least eight counts, all reported as P. bicalyculata (Retz.) Nees , in Daniel et al. 2000). Other counts in the genus are n =10 ( Narayanan 1951 for P. paniculata , as P. bicalyculata ), n = 24 ( Ge et al. 1989 for P. japonica (Thunb.) Bremek. ), and n = 21 ( Takizawa 1957 for P. hyssopifolia (Burm.f.) Merr. , as P. salicifolia Hassk. ). It is noteworthy that counts of n = 15 are known for species of Peristrophe in each of the two clades of Diclipterinae ( Kiel et al. 2017) that contain species of that genus.

The closest relatives of species of Peristrophe in Diclipterinae are Dicliptera , Hypoestes Sol. ex R. Br. , and Rhinacanthus Nees. All of these genera share a common chromosome number of n = 15, which is likely the ancestral basic number of the monophyletic “core Diclipterinae” lineage noted by Kiel et al. (2017). Within “core Diclipterinae” polyploidy (e.g., n = 30) is also known for Dicliptera , Hypoestes , and Peristrophe . Polyploidy is not known for Rhinacanthus (Daniel and Chuang 1998; Daniel et al. 2000), and no chromosome numbers have been reported for the Australian genus Xerothamnella C.T. White , a species of which is nested in a clade of Peristrophe ( Kiel et al. 2017) .

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.