BERGGREN1, SCOTT THOMAS*, SANGTAE LEE2, AND JUN WEN3. 1,3Department of Biology, Colorado State University, Fort Collins, CO 80523 USA, , 2Department of Biology, Sungkyunkwan University, Suwon 440-746, Korea. - Phylogenetic studies in the Amygdaloideae (Rosaceae) using ITS and ndhF sequences.
The relationships among the members of the economically important
subfamily Amygdaloideae (Rosaceae) are in need of a phylogenetic
reappraisal. Sequences of the ITS regions of nrDNA and the
ndhF gene of cpDNA were employed to reconstruct the phylogeny
of the subfamily, and evaluate the traditional classification schemes
of this group. The two data sets are congruent in several aspects: (1)
the genera Prunus s.l. and Maddenia form a monophyletic
group, with Maddenia being nested within Prunus; (2)
Exochorda (traditionally placed in subfamily Spiraeoideae) is
closely allied with the Amygdaloideae; (3) two major clades are
recognizable within Prunus: one consisting of the subgenera
Amygdalus and Prunus, and the other containing the
subgenera Cerasus, Laurocerasus, and Padus
(including Maddenia); and (4) a few members of the subgenus
Cerasus (Prunus besseyi and P. tomentosa) are
placed within the clade consisting of subgenera Amygdalus and
Prunus, suggesting that subgenus Cerasus is
polyphyletic. The two analyses differ in the placement of the core
cherry group (subgenus Cerasus) and the position of
Maddenia. The combined analysis has a higher resolution within
Prunus and places Maddenia sister to Prunus s.l.
Traditionally, Maddenia has been separated from Prunus
because of the calyx lobes (10 as opposed to 5 in most Prunus)
and unisexual flowers. This study suggests the need for further
evaluation of the phylogenetic position of Maddenia.
Key words: Amygdaloideae, Prunus, Rosaceae, systematics, taxonomy