Phylogenetic placement, floral anatomy, and morphological characterization of the North African pastoral halophyte Atriplex mollis Desf. (Amaranthaceae)

Abstract

Atriplex mollis Desf. (Amaranthaceae), a North African endemic halophytic species, is further described in this study.Phylogenetic analysis based on a combined dataset of ITS and ETS rDNA and atpB-rbcL and trnK cpDNA showed that A. mollis isclosely related to the Malta- and Gozo-endemic Cremnophyton lanfrancoi Brullo & Pavone. Given this close phylogenetic relationship,A. mollis is also considered among the oldest species of Atriplex, together with C. lanfrancoi. Molecular data also suggest that A. mollis inNorth Africa, C. lanfrancoi on Malta Island, and Atriplex cana Ledeb. in Eurasian semideserts constitute a separate clade within the tribeAtripliceae. As an 18-month-old shrub, A. mollis can reach a mean height of 44.06 ± 8.09 cm with a leaf area around 1.24 ± 0.15 cm2,and can produce seeds in order of 113.08 ± 28.52 g plant−1. The anatomy of A. mollis shows the presence of male and female developedflowers. Hermaphroditic flowers that may lead to the appearance of male flowers with underdeveloped female organs were rarely found.Three main shapes of ovule (campylotropous, amphitropous, and orthotropous) were found in A. mollis.