C. Brochmann et al., Multiple diploid hybrid speciation of the Canary Island endemic Argyranthemum sundingii (Asteraceae), PLANT SYS E, 220(1-2), 2000, pp. 77-92
There are several well-documented examples of multiple hybrid origins of po
lyploid species. Herein we report the first, to our knowledge, explicit exa
mple of a species that most probably has originated recurrently by diploid
hybrid speciation. Genetic relationships and stabilization of two Argyranth
emum populations of putative hybrid origin on Tenerife, the Canary Islands,
were investigated using chromosomal, morphometric, and fertility analyses
of cultivated progeny families and artificial Fl and Fz hybrids. These data
were compared to a recently published chloroplast DNA phylogeny of the gen
us, in which the same populations were included. The results suggest that t
he two populations must be referred to a single species, A. sundingii, whic
h is diploid, fully fertile, genetically stabilized, and occurs in an ecolo
gically intermediate habitat opened by deforestation, and that this species
has originated at least twice following local hybridization in two valleys
. The same parental species were involved in each origin; the montane A. br
oussonetii and the coastal A. frutescens. The montane species was the chlor
oplast donor in one of the valleys and the coastal species in the other.