A new Australian genus, Androcalva, separated from Commersonia (Malvaceae s.l. or Byttneriaceae)

Abstract

A new genus, Androcalva C.F.Wilkins & Whitlock, is here described and includes 22 species previously described as Commersonia, four species formerly described as Rulingia and seven new species, including A. aphrix C.F.Wilkins, A. perlaria C.F.Wilkins, A. bivillosa C.F.Wilkins, A. adenothalia C.F.Wilkins, A. fragifolia C.F.Wilkins, A. incilis C.F.Wilkins and A. lachna C.F.Wilkins. Rulingia pauciflora Turcz. is here placed in synonymy with C. gaudichaudii J.Gay as A. gaudichaudii. Recognition of Androcalva is supported by the results of a previous molecular phylogenetic analysis demonstrating that neither Rulingia nor Commersonia as previously circumscribed is monophyletic. Species of Androcalva share characters of extrorse anther dehiscence and glabrous central staminodes. In contrast, species in the redefined Commersonia have anthers with sublatrorse dehiscence and hairy central staminodes. Taxonomic descriptions, a key, distribution maps, conservation status and illustrations are presented.

Polyphyly of Rulingia and Commersonia (Lasiopetaleae, Malvaceae s.l.)

“…1). These species all share characters of prominently winged fruit, scarcely tuberculate seed coats, an articulated pedicel, petal ligules and staminodes that are narrowly spathulate and far exceeding the calyx (Wilkins and Whitlock 2011b). They also share a unique 20-bp insertion in sequences of the trnL intron.…”

“…For example, within Clade 2, Commersonia rosea, C. pearnii, C. pedleyi and C. johnsonii appear very closely related to a species formerly placed in a different genus, Rulingia procumbens. The first four species all have very wide basal lobes on the petal and a petal ligule that is narrowly obovate, and C. rosea, C. johnsonii and C. pedleyi all have distinctive narrowly triangular acuminate staminodes (Wilkins and Whitlock 2011b). However, R. procumbens has narrow lateral petal lobes and ovate staminodes.…”

“…Sequences of the two species are intermingled within Subclade G and these taxa are sympatric at a regional scale in Western Australia (Wilkins and Whitlock 2011b). One of the two species, C. pulchella, also shows substantial variation in leaf morphology (Wilkins and Whitlock 2011b).…”

“…Accordingly, Wilkins andWhitlock (2011a, 2011b) used these phylogenetic results and the androecial characters described above to reclassify all species of Commersonia and Rulingia, resulting in 25 species in Commersonia (of which 20 are sampled here) and 33 species of Androcalva (of which 26 are sampled here). For future reference, we include in Table 1 both the manuscript names and new names from the Index of scientific names (Wilkins and Whitlock 2011b) for all taxa sampled in the present study.…”

“…Eighty individuals of Rulingia and Commersonia were sampled for three chloroplast markers, representing 46 species and 80% of species in these taxa (Wilkins and Whitlock 2011b, Index of scientific names). Twelve outgroups were chosen, including representatives from all eight other genera of Lasiopetaleae (Keraudrenia, Seringia, Hannafordia, Maxwellia, Lasiopetalum, Guichenotia, Lysiosepalum and Thomasia), two from Byttnerieae (Abroma and Kleinhovia), and two from Theobromeae (Theobroma and Guazuma), following results of previous phylogenetic analyses of Byttnerioideae (Whitlock et al 2001;Wilkins 2002; Table 1).…”