Convergent evolution of flower polymorphism in Narcissus (Amaryllidaceae)

Abstract

Summary• We present new results on morphological variation for style polymorphism and perianth features in the seven species of Narcissus sect. Apodanthi and in N. pallidulus (sect. Cyclaminei), which exhibits a wide array of flower conditions: heterostyly, style dimorphism of variable reciprocity, and style monomorphism.• There is a significant association between perianth morphology and style polymorphism in the studied species. Among significant flower features, the two heterostylous species show pendulous flowers. Most style-dimorphic species have patent flowers, whereas monomorphic and one style-dimorphic species display erect flowers.• Interpretation of a chloroplast ( trn L-trn F) phylogeny of species representing most sections in the genus leads us to conclude that the two heterostylous species have independent origins, supporting previous hypothesis of convergence of heterostyly in Narcissus . Remarkable resemblance of flower features between both species indicates that pollinator activity might have driven flower convergence.• A second chloroplast ( trn T-trn L) phylogeny in sect. Apodanthi helps elucidate some evolutionary transitions in moulding heterostyly. Stylar dimorphism appears to precede distyly and style monomorphism. Population studies on style dimorphic and monomorphic species of Narcissus are congruent with a pollinator-mediated process also involved in a shift to monomorphism.

Pollinator shifts and the loss of style polymorphism in Narcissus papyraceus (Amaryllidaceae)

“…These authors argued that disassortative mating in S‐plants was a consequence of the relatively high reciprocity between the S‐stigma and the lower anther level of the L‐morph, and a well‐developed reverse herkogamy, which prevented assortative mating. Herkogamy remarkably varies among Narcissus species (Pérez et al. , 2004), and it is smaller in S‐flowers of N. papyraceus than N. assoanus (mean ± SE for six dimorphic populations in N. papyraceus : 2.6 ± 0.2 mm; N. assoanus 5.9 ± 0.2 mm, data from Cesaro & Thompson, 2004), meaning that lower anther level of S‐flowers is closer to S‐stigmas in N. papyraceus than N. assoanus .…”

New evidence for the Darwinian hypothesis of heterostyly: breeding systems and pollinators in Narcissus sect. Apodanthi

“…The seven species are some of the earliest species blooming in Mediterranean communities, where they are frequently among the first to flower (Herrera, 1995). Additional information can be found in Pérez et al . (2004).…”

“…All species were subject to experimental work to obtain comparable data on breeding systems and pollinator fauna relevant to evolution of heterostyly. These data were compared with previous results on style and perianth polymorphism of these species (Pérez et al ., 2004). Reproductive shifts in the course of evolution were investigated by means of phylogenetic analysis of plastid sequences of the trn T ‐trn L, trn L ‐trn F and trn Q ‐trn R spacers.…”

The evolution of polymorphic sexual systems in daffodils (Narcissus)

“…The single instances of distyly ( N. albimarginatus section Apodanthi ) and tristyly ( N. triandrus section Ganymedes ) are clearly not homologous and represent an evolutionary convergence unique to the Amaryllidaceae ( Fig. 2; Pérez et al ., 2003). Narcissus albimarginatus occurs within a clade with stigma-height dimorphism, so that distyly probably evolved from this ancestral state through the evolution of reciprocal herkogamy.…”