Ekimia , a new genus of Umhelliferae , and two new taxa of Prangos Lindl. (Umbelliferae) from southern Turkey

Studies on recent collections of mature fruiting material of Prangos bommuelleri Hub. Mor. & Reese have resolved the taxonomic placement of this enigmatic species. The new monotypic genus Ekimia H. Duman & M.F. Watson is proposed to include this taxon: E. bommuelleri (Hub.-Mor. & Reese) H. Duman & M.F. Watson comb, now Two new Prangos taxa, P. platychloenae Boiss. ex Tchih. subsp. engizekensis H. Duman & M.F. Watson subsp. now, and P. heyniae H. Duman & M.F. Watson sp. now, arc also described.


I N T R O D U C T I O N
Prangos bommuelleri Hub.-Mor. & Reese (Huber-Morath. 1945: 152) is a distinctive umbellifer, and a narrow endemic restricted to a small area of Burdur Vilayet. SW Anatolia. Until recently it has been known only from the original immature type collection. However, new gatherings with mature fruits have enabled the resolution of the long-standing taxonomic problem of its generic placement.
In their treatment of Prangos Lindl. for the Flora of Turkey, Herrnstadt & Heyn (1972) included P. bommuelleri at the end of the account amongst the 'incompletely known species'. They pointed out that it differed from all other species of Prangos by the apparently winged secondary ridges of the developing fruit, rather atypical form of the leaves, and comparatively few, very long umbel rays. They considered that the species should probably be excluded from Prangos, but mature fruit would be needed before it could be referred to another genus. Later, the same authors published a complete monographic treatment of Prangos (Herrnstadt & Heyn, 1977), and again this enigmatic species was treated as doubtful, possibly meriting generic status. Since this detailed monograph, problems in generic circumscription have been addressed by Pimenov & Tikhomirov (1983), and the Iranian elements treated in Flora Iraniea by Herrnstadt & Heyn (1987). However, as no further material was available, nothing more could be said about the fate of the enigmatic P. bommuelleri.
During fieldwork for the Turkish Endemic Plant Project in June 1993, material of an unusual umbellifer was collected. On further visits to the site in July-August 1993. July 1995 and June July 1996, more material was gathered providing a range of specimens bearing good flowers and fully mature fruits. This material has been carefully compared with the holotype of Prangos bommuelleri at Geneva, and judged to be conspecific. The new specimens confirm that P. bommuelleri is anomalous within Prangos on account of the distinctively winged secondary ridges of the fruit, 3-ternate leaves and few, very long umbel rays, and fruit anatomy (see Figs 1,2). We cannot place this unusual species within any other known genus, and therefore transfer it into the new monotypic genus Ekimia H. Duman & M.F. Watson. In addition to resolving this taxonomic problem, we have also identified two new taxa of Prangos, and these are described below.
Fruit anatomy from mericarp TS and mascerations was studied for all three plants (for methodology see Barclay & Watson, 1998). The two new Prangos taxa show the typical Prangos architecture (Fig. 3) as described by Pimenov & Tikhomirov (1983). The mesocarp is made up of two distinct layers: the outer epimesocarp of unmodified parenchymatous cells with small secretary ducts, degenerating at maturity (as in the fruit section illustrated); and the inner layer of aerenchyma, also with scattered small secretary cells. True vittae are concentrated in a ring on the innermost layer of the mesocarp. These vittae arc small and numerous in TS. but the longitudinal view from a masceration (Fig. 3b) shows them to consist of long, anastomising and short, unconnected vittae. The endosperm is characteristically indented on the commissural side. Ekimia has an entirely different fruit anatomy (Fig. 2b), with unilayered mesocarp (also degenerating at maturity); a more typical Apioideae arrangement of six large discrete vittae running unbranched for the length of the mericarp, alternating with vascular bundles; and entire endosperm.
Distribution and ecology. Endemic to S Turkey, part of the Irano-Turanian fioristic element. Rocky slopes; 2100 2700m. Flowers July, fruits August. bracteis minoribus 5-10cm longis (non 10 15cm). bractcolis minoribus 3 5mm longis (non 5-7mm). petalis extus glabris (non pubesccntibus) ct anthcris glabris (haud ad apicem comosis) differt. Although similar to Prangos corymbosa Boiss. we consider the differences in leaf morphology, sexual function of the inflorescence, and petal pubescence warrant recognition as a distinct species. Studies wild populations and herbarium specimens show that plants of P. heyniae consisently lack primary pairs of leaf segments, have hermaphrodite terminal and lateral umbels, and the petals arc glabrous. In P. corymbosa the primary segment pairs of the leaves are nearly sessile, the lateral umbels have only male flowers, and the petals are pubescent. This species is named in memory of the late Professor Chaia C. Heyn, previously of the Hebrew University. Jerusalem, who has made a major contribution to the taxonomic knowledge of the genus Prangos.