The geometry of gender: hyper‐diversification of sexual systems in Urtica L. (Urticaceae)

Abstract

Urtica L. (Urticaceae) is generally reported as a genus of monoecious and dioecious taxa. However, the gender information found in the literature does not at all reflect the actual diversity of gender patterns in Urtica. Dioecy appears to be truly absent from Urtica, but otherwise there has been a major diversification in the geometry of gender and no comparable patterns exist in other plant groups. Thus, we here define technical terms for all unique architectural types of monoecy found in Urtica and closely related genera and reconstruct the ancestral gender states in a Bayesian framework. Our studies are based on a near‐comprehensive sampling, including 61 of the 63 Urtica species recognized. We report polygamy, two types of gynodioecy and five different architectural types of monoecy. A total of 15 switches appear to have taken place within the genus. Although gender characteristics have diversified strongly, they are relatively conserved within clades. Monoecy is the predominant sexual system within Urtica and specifically basiandrous monoecy (i.e. basal inflorescence branches of each individual male only, apical branches female) is the most widespread type, reported for 11 different clades. In particular, it characterizes the basally branching pilulifera‐clade and the sister genus Zhengyia, and may thus represent the plesiomorphic condition for Urtica. Gender distribution and gross morphology appear to evolve largely independently from each other and gender distribution is largely independent of growth habit. However, polygamous taxa are most common amongst rhizomatous perennials (one‐third of the taxa).

Polyploid evolution: The ultimate way to grasp the nettle

“…Urtica dioica is characterized by huge variation mirrored by a high number of intraspecific taxa distinguished either solely based on morphological characters (e.g. various types of indumentum [54–56]) or with consideration for sexual morphs (predominantly stochastically occurring [54, 55, 57]). Finally, polyploidy is a truly substantial source of variation in U. dioica .…”

Nettle, a Long-Known Fiber Plant with New Perspectives

“…gracilis) subspecies have been reported [52]. Große-Veldmann and Weigend [53] also suggested that no strict dioecious species belong to the genus Urtica. Urtica dioica and all its subspecies are polygamous, with Urtica dioica subsp.…”

Intraspecific Variability of Stinging Nettle (Urtica dioica L.)

“…Stinging nettle ( Urtica dioica L., Urticaceae family) is a wild-growing herbaceous perennial occurring almost all over the world. It grows mainly on damp and nitrogen-rich soil at partly shaded sites, including meadows, forests edges and brushwoods [ 1 , 2 , 3 , 4 ]. The nettle is highly polymorphic in terms of its ploidy level, developmental traits and chemical composition.…”

“…So far, plenty of subtaxa, including subspecies, morpho- and ecotypes, varieties and hybrids have been recognized within the species [ 5 , 6 ]. Thus, it is treated as a complex taxonomic group described collectively as U. dioica sensu lato [ 1 , 4 , 7 ].…”