Putative floral brood-site mimicry, loss of autonomous selfing, and reduced vegetative growth are significantly correlated with increased diversification in Asarum (Aristolochiaceae)

Spatial and temporal variation in volatile composition suggests olfactory division of labor within the trap flowers of Aristolochia gigantea

“…These kleptoparasitic flies (Trachysiphonella ruficeps) steal food from other insects, and in this case specifically imbibe the secretions from mirid bugs killed by other arthropods (Oelschlägel et al, 2015). Finally, the larger Aristolochiaceae, which now includes the former Piperaceae, Saururaceae and Hydnoraceae (APG, 2016), includes additional pollinator niches, including fungal mimicry in the ground-blooming genus Asarum and the cauliflorous Aristolochia arborea (Kaiser, 2006;Sinn et al, 2015;Vogel, 1978). The fetid, fleshy flowers of Hydnora africana, a root parasitic species, emit sulfur volatiles (Burger et al, 1988) and form subterranean chambers that trap tenebrionid beetles in southern Africa, suggesting a rotting-hide niche (Bolin et al, 2009).…”

Asarum rosei (Aristolochiaceae), a new species from the Blue Ridge Escarpment of North Carolina, USA

“…The distinctive leaf morphology of A. rosei allows one to confidently identify individuals when in vegetative condition; this may help parties interested in surveying lands for conservation purposes or other botanists to identify new populations of this species throughout the year. The flowers of section Hexastylis species have been hypothesized to mimic fungal brood sites for fungus gnats (see Sinn et al, 2015b), and the adaxial calyx sculpturing of A. rosei flowers has been photographed with dipteran larvae present throughout ( Figure 5). Sympatry between A. rosei and A. shuttleworthii represents another similarity to some populations of A. heterophyllum in South Carolina and Georgia where I have found those two species, often along with A. arifolium Michx., in mixed populations with segregated flowering periods (Sinn, 2015).…”

“…Asarum (Aristolochiaceae) comprises approximately 110 species (Cheng and Yang, 1983;Huang et al, 1995;Kelly, 2001;Sinn et al, 2015a) whose reproductive biology and diversity is more poorly known (Kelly, 1997;Sinn et al, 2015b) than would be expected given the charismatic and attractive flowers, broad geographical distribution, and use in horticulture. During 1998, Mark Rose discovered a population of Asarum plants along Wilson Creek in Caldwell County, North Carolina, USA that were unassignable to any known species.…”

“…Recent work on the phylogenetic relationships, character-associated diversification, and taxonomy of Asarum (Gaddy, 2011;Sinn, 2015;Sinn et al, 2015aSinn et al, , 2015b have sparked a renewed regional interest (Keener and Davenport, 2015;Weakley, 2015;Diamond, 2016) in the rank-level designations of the infrageneric categories established by Araki (1937Araki ( , 1953, Cheng and Yang (1983), Kelly (1997Kelly ( , 1998Kelly ( , 2001), Sugawara (2006), and Sinn et al (2015a). A discussion of the perspective of these authors is warranted here, not simply to provide historical background but also to provide context for why this new species is named in Asarum, rather than in the Rafinesque genus Hexastylis (1825).…”

“…The phylogenetic investigations of Sinn et al (2015aSinn et al ( , 2015b fail to unequivocally support the monophyly of section Hexastylis, and suggest that a unique combination of plesiomorphic character states and phylogenetic signal encapsulated in the plastid genome, rather than the presence of any single synapomorphic character state, support what has been designated as Asarum subgenus Heterotropa section Hexastylis (See Sinn et al 2015a for discussion and appendix 3 for a key to Asarum sub-generic ranks). While rank-level taxonomic designations are arbitrary, with the exception of the condition of monophyly, I propose that in order to make a strong case for the recognition of Hexastylis, the presence of at least a single morphological synapomorphy and unequivocal molecular support for a single evolutionary origin of the genus should be reported.…”