Running title : An unusual stylar polymorphism in Narcissus 2 3 Stylar polymorphism on the edge : unusual flower traits in Moroccan 4 Narcissus broussonetii ( Amaryllidaceae ) 5 6

24 Heterostyly and related polymorphisms (e.g. stigma-height dimorphism) have been used 25 as model systems to study the origin and maintenance of plant population variability. 26 Stigma-height dimorphism frequently occurs in Narcissus and it is associated to a 27 particular flower shape. Here we describe a new, peculiar case of stigma-height 28 dimorphism in N. broussonetii, a species in the margin of the geographic distribution 29 range of the genus. We determined the stylar condition of N. broussonetii and its 30 variation across populations, analyzed perianth morphology and its relation with stylar 31 variation, and compared this with other stylar dimorphic species of the genus. We also 32 studied the incompatibility system and pollination ecology of the species. Narcissus 33 broussonetii is a style dimorphic species, as suggested in early studies but later 34 neglected, and displays unusual flower morphology, with a very long flower tube and 35 virtual absence of a corona. The species presents a late (ovarian) acting incompatibility 36 system and crosses within and between morphs are fertile. We observed short-tongued 37 diurnal and long-tongued nocturnal pollinators. Our findings confirm that the presence 38 of the observed dimorphism across populations is most probably the result of the joint 39 action of a non-heteromorphic incompatibility system, extremely long and narrow 40 flower tubes, and a combined role of shortand long-tongued pollinators. 41 42