Delimitation of the genera Katapsuxis , Cnidiocarpa and Selinum (Umbelliferae) and the taxonomical synopsis

a continuous scabrous wax layer that masks cuticular foldings. In other species, the boundaries of the cells are indistinct or visible only on some areas of the surface, the cuticle is striate and rugulate, and wax is absent. On the basis of the obtained observations and previously published molecular phylogenetic studies, Cnidiocarpa , Katapsuxis and Selinum were shown to be separate genera, substantially distant from the type species of Cnidium and Ligusticum . Keys have been compiled to identify the abovementioned genera, their species, and (in the case of Kata psuxis silaifolia ) varieties, the synonyms are listed, and distribution data are given. The most important diagnostic features are the micromorphology of the fruit surface, the shape and dissection of the leaf segments, the shape of the leaf sheaths, the shape of the stylopodia, the length of the styles, and the secretory ducts number.

While the plants of the Umbelliferae are easily recognizable (especially the subfamily Apioideae, which includes the genera under consideration), the circumscription of its genera was disputed for centuries and is far from being resolved today. There are more than 300 nomenclatural combinations in the rank of species in Ligusticum, more than 200 combinations in Selinum and more that 70 ones in Cnidium (International Plant Name Index, 2018), and most of these combinations are out of use now.
Hand (2011) probably followed Leute (1970) and used a broad concept of the genus Selinum; he regarded the genera Cnidiocarpa, Kadenia Lavrova et V. N. Tikhom., Katapsuxis, and Cnidium as synonyms of Selinum in contravention of morphological and molecular data.
in glycerol-alcohol-water; free-hand sections were processed with phloroglucinol-hydrochloric acid and kept in glycerol. Microphotographs were made with the Olympus BX41 microscope and Olympus DP25 camera; the device "RA-4" was used for drawings. Fruit morphology was studied with a stereomicroscope Olympus SZ61 (x45) equipped with the digital camera Olympus.

Fruit micromorphology
In species under consideration, the rib crests are rather uniform: cell borders are indistinct, surface longitudinally sulcate (except the fruits of Ligusticum scoticum, that are all over covered by uniform cells), cuticle striate. Microsculpture of rib slopes and valleculas is more diverse and is described below. Stomata are absent in the valleculas and presented on rib slopes. Stomata are usually rare, 1-3 per 1 square mm 2 , sometimes no stomata are visible on an image of 1 mm 2 .

Discussion / Taxonomy
The fruits of the five genera have similar appearance, that was a source of numerous confusions and nomenclature changes: mericarps glabrous, ovate or elliptic, terete or slightly compressed dorsally, with conspicuous winged ribs, narrow commissure, endosperm with flat on the commissural side. Katapsuxis, Selinum and Cnidiocarpa have a lot of common in their habit: glabrous perennial polycarpic herbs with short horizontal rhizomes and several large basal leaves. In the dense plant communities they have usually one flowering/fruiting stem, and in environment with low competition in wild or in botanical garden the individuals become large and multistemmed. Leaves ovate or triangular in outline, 3-4-pinnatisect, first order segments with petiolules.
On the base of morphological and molecular data we regard Katapsuxis, Selinum and Cnidiocarpa as related, but separate genera, which are rather distant from Ligusticum s. str. and Cnidium s. str.
Histological structure of its fruit is unknown. Leute (1970) studied immature fruits with 1-2 secretory ducts per vallecula and 4 ducts on commissural side; Arenas Posada et al. (1993) also could not find mature fruits; Castroviejo (2003) published a small image of transection of mature fruit: it resembles S. carvifolia, with 1-2 ducts per furrow. According to Vallejo-Roman et al. (2006) S. carvifolia and S. broteri are united in the subclade with high bootstrap.