Abstract. Biebersteiniaceae comprise a single genus with four species of perennial herbs occurring from central Asia to Greece. A previous molecular phylogenetic study placed one of the species in an isolated position in Sapindales, while morphological studies had placed Biebersteinia in or near Geraniaceae, albeit doubtfully. We tested the monophyly and placement of the family with data from the chloroplast genes rbcL and atpB obtained for all four species, other major clades of Sapindales and outgroups for a total of up to 114 taxa. Parsimony, Bayesian, and likelihood analyses place Biebersteinia in Sapindales, possibly as sister to the other eight families. Strict and relaxed molecular clocks constrained with fossils of Biebersteinia and up to eight other Sapindales suggest that the Biebersteinia crown group diversified in the Oligocene and Miocene, while the stem lineage dates back to the Late Paleocene. Ages for other sapindalean families are earlier than those obtained in more sparsely sampled analyses, although estimates for Burseraceae agree surprisingly well. Ancestral area analyses suggest that Biebersteinia expanded from the eastern part of its range (i.e. Tibet and Inner Mongolia) to the west, although analyses are hampered by the unclear sister group relationships.

Phylogenetic analysis of rbcL and atpB gene sequences from Biebersteinia Stephan (represented by B. orphanidis Boiss.) and from selected taxa of the rosids I and II clades does not support traditional grouping of this genus in Geraniaceae s. s. nor in Geraniales, but indicates strong support for a position nested within Sapindales (as recently delimitated). The rbcL and atpB phylogenies obtained were congruent but differently resolved and do not link Biebersteinia to any other clade within Sapindales. Biebersteinia is on a long branch on its own which, given the particular combination of apomorphic morphological characters, justifies familial status.

No abstract

Biebersteinia orphanidis was considered extinct from Greece and Europe as it had not been collected since Orphanides' type collection of 1851. Its rediscovery is reported here from a mountain close to the classical locality. The species serves as a distinct phytogeographical link between the floras of Greece and Anatolia. In Greece, at least, it grows in a critically low number of individuals. Data on the species habitat and population status are given, and potential threats to its survival are discussed.

Biebersteinia, a perennial herb of five species distributed from Greece to Central Asia, was long considered to be placed in, or near Geraniaceae. Recent molecular analyses, however, have shown that the genus is the sole member of the family Biebersteiniaceae in Sapindales (not including Geraniaceae). Here, we report the embryological features of Biebersteinia and provide embryological corroboration for the molecular sapindalean affinities of the genus. We compared its embryology with those of eight other families of Sapindales, as well as with those of the related orders Huerteales, Malvales, and Brassicales. Overall comparisons showed that Biebersteinia fits in Sapindales because of the presence of anther tapetal cells with polyploid nuclear mass and non-fibrous exotegmen. Further, the genus is characterized by three-celled pollen grains, tetrasporic 16-nucleate Penaea-type female gametophyte, unitegmic ovules, pseudoporogamy, and the chalaza shifting its position near the concave side in the post-fertilization stage. A considerable number of autapomorphies, combined with the lack of synapomorphies with other sapindalean families, supports placing Biebersteinia in its own family. Biebersteiniaceae appear to represent an early divergent lineage of Sapindales. Previous descriptions of seed coats, which were considered to have developed from "bitegmic" ovules, were revised.