Résumé
Lupinus mariae
-
josephi
H. Pascual is an intriguing lupin species recently discovered in the Mediterranean region. New data from seed coat micromorphology, cytology, and DNA sequences were generated in order to extend our knowledge on this species and to examine its evolutionary relationships within
Lupinus
. This species shows morphological similarities with the Mediterranean smooth seeded species of sections
Micranthi
and
Lutei
. It shares the same chromosome number 2
n
= 52 with the latter Old World taxa, but also with unifoliolate lupins from Florida. Besides,
L. mariae
-
josephi
exhibited a seed coat micromorphology “intermediate” between the rough and the smooth seed coat types. Phylogenetic analyses using ITS and ETS nrDNA spacers, and the
LEGCYC1A
locus supported
L. mariae
-
josephi
as a distinct Old World line, placed out of the
Scabrispermae
, but without clear placement amongst the Mediterranean smooth-seeded lineages. Unexpectedly,
LEGCYC1A
data revealed phylogenetic affinities between
L. mariae
-
josephi
and
L. villosus
, a unifoliolate North American lupin that might have experienced a reticulated evolutionary process. All together, the data underline the phylogenetic interest of
L. mariae
-
josephi
in
Lupinus
and the need of additional investigations in order to definitely elucidate its enigmatic status. Moreover, as
L. mariae
-
josephi
is one of the rare Old World lupins strictly restricted to poor basic soils, it opens new perspectives of ecological and agronomic interests in the wide areas of poor calcareous soils in the Mediterranean region.