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Background: The recently proposed recircumscription of the genus Atraphaxis (incl. Atraphaxis section Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli and Polygonum sect. Spinescentia Boissier (=A. sect. Polygonoides S. Tavakkoli, Kaz. Osaloo & Mozaff.) makes this genus fairly heterogeneous and therefore almost undefinable based on morphology. A critical comprehensive reappraisal of the group is necessary.Methods: Using the DNA sequence data (ITS1&2 regions of nrDNA and combined trnL intron + trnL–F IGS and rpl32–trnL(UAG) IGS regions of plastid genome), Maximum Likelihood (ML) and Bayesian analyses (BI) were applied for phylogenetic reconstructions of the tribe Polygoneae with special attention to Atraphaxis, and related taxa. Maximum parsimony reconstructions of the evolution of perianth morphology and sporoderm ornamentation in the tribe Polygoneae were also performed. Life history, morphology of shoots, leaf blades, ocreas, perianth and achene morphology, ultrasculpture of achene surface, and pollen morphology were compared, and SEM and LM images were provided.Principal findings: The genera Atraphaxis and Polygonum were found to be widely polyphyletic. The rarest and morphologically remarkable endemic of Tian-Shan and Pamir Atraphaxis ovczinnikovii (Atraphaxis sect. Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli) was confirmed to be a sister of the clade (Atraphaxis + Polygonum sect. Spinescentia) in plastid topology. The genus Bactria (=Atraphaxis sect. Ovczinnikovia), which circumscribes two species, is newly established as a result of this analyses. Morphological data confirm the originality of the taxon.Discussion: We are arguing for a narrow delimitation of Atraphaxis with petalloid segments and striato-perforate sporoderm ornamentation as morphological synapomorphies. The recently proposed inclusion of Polygonum sect. Spinescentia in Atraphaxis is fairly questionable from a morphological standpoint. The rank of Polygonum sect. Spinescentia requires further clarification. The generic composition of the tribe Polygoneae also requires future reappraisals.

Yurtseva, 0. V. 2001. Ultrasculpture of achene surface in Polygonurn section Polygonurn (Polygonaceae) in Russia. -Nord. J. Bot. 21: 513-528. Copenhagen. ISSN 0107-055X.Based on SEM examination of 47 specimens and 33 species from Russia and Europe, this is a survey of achene surface ultrasculpture in 6 subsections of annual species of Polygonurn. Early and late achenes detected in most species possess sound distinctions in achene shape, size, color and exocarp structure. Late achenes with early and fast seed germination preserve exocarp structure typical for premature achenes of both types: thin colorless walls and vast cavities, thin cuticle and insignificant wax deposits. Early achenes destined for long-term preservation in soil are thickwalled and covered with thick and smooth cuticles and wax layers. The structure of achene surfaces changes substantially during maturing, especially in early achenes: coarse or foveo-rugulate background becomes minutely rough, foveosmooth or minutely reticulate. Verrucae are not obligatory ornaments. Depending on their location and arrangement of exocarp cells the surface is evenly verrucate (subsect. Patula Tzvel.), linear-verrucate (subsect. Sulsuginea Tzvel.) or striateverrucate (subsect. Hurnifusa Tzvel., most species in subsect. Polygonurn). Smooth and glossy achenes are more common in permanently wet environments (subsect. Maritirna Tzvel., Arenaria Tzvel., I? arenastrurn and I? calcaturn from subsect. Polygonurn). In places with fluctuating availability of water the achenes have heavier sculpturing and thicker cutin and wax coverings. A broad range of surface sculptures in some species and their similarity across taxonomically distant taxa decrease the value of the characters for taxa identification. 0. K Yurtseva.

Maximum Likelihood (ML) and Bayesian analyses (BI) applied for 3-plastid loci (cpDNA trnL(UAA) intron, trnL–trnF IGS, and rpl32–trnL(UAG) IGS regions) / 65 tips matrix resulted in preliminary phylogenetic reconstruction of the genus Atraphaxis. In combination with the morphological data the obtained phylogeny appears sufficient for recognition of challenging taxonomic entities. We found that a collection of Atraphaxis from the Dzungarian Gobi, which appears to be phylogenetically related to A. pungens, is morphologically different from the latter by the predominantly dimerous perianth and gynoecium, shorter outer perianth segments, and the absence of the spiny shoots. It also differs from all other species of Atraphaxis that occur in Mongolia and neighboring countries. As a result, we described the novel endemic species Atraphaxis kamelinii O.V.Yurtseva sp. nov. More investigations are necessary to fully understand the origin of the newly described species.

Variability of morphological characters in Pimpinelk tragium VILL. group was investigated using herbarium material natural populations field sampling and cultivated plants. As a result of anatomical and morphological research, and by means of Principal Component Analysis and Canonical Variance Analysis, two polymorphic species were distinguished -P. tragium VILL. with hairs 0.05-0.2 mm long and P. polyclada BOISS. & HELDR. with hairs 0.3-1 mm long. Both polymorphic taxa include forms differing in density of pubescence and leaf dissection. Distribution of pinnatisect and bipinnatisect leaf forms over the range corresponds to the pattern of summer precipitation and duration of the drought period. In P. tragium several ecotypes could be distinguished, differing in leaf shape and structure, life history and development rhythm. However, recognition of infraspecific taxa is inexpedient and can misrepresent the complicated pattern of morphological variability within P. tragium VILL. IntroductionPimpinella tragium VILL. is a widespread complex of species with great morphological variability and confused taxonomy. It is distributed in the Mediterranean from Spain to Lebanon, in North-West Africa, Asia Minor, the Caucasus, the Central Kopet-Dagh and in the South of the East European Plain.Most taxonomists (BOISSIER 1872; HALACSY 190 1 ; WOLFF 1927) considered P. rragium VJLL.Z u s a m m e n f a s s u n g to be a polymorphic species with several varieties, some widespread over the range of P. tragium, and others are restricted in their distribution. Nevertheless some hardly distinguishable races from Russia and neighbouring tenitories have been treated until now as species (SCHISCHKlN 1950a, b; PIMENOV & TIKHO-MIROV 1981, 1995. SCHISCHKIN recognized nine species, differing in leaf blade dissection, umbel ray number, hair density, fruit size and stylodium length, characters used to char-480 Feddes Repert., Berlin 109 (1998) 7-8 acterize varieties of P. trugiurn in Europe. He did not take into account variability of the characters and transitional forms, so the species identification has been a great problem.TUTIN ( 1968a, b), MATTHEWS ( 1972) Minor.Every taxon described in the P. tragiurn group was characterized by several features, each representing only a small part of general range of values observed in this group. The broad morphological variation of some taxa and transitional forms among them has complicated the taxonomy of this polymorphic group, making the taxonomic rank and relations of the intraspecific taxa uncertain.The aims of our research were I ) to estimate morphological variability in the P. trugiurn group, 2 ) to throw light in differentiation trends in P. trugiurn and 3) to make new taxonomic proposals. Material and methodsWe studied about 2000 specimens from 20 herbaria (B, BAK, BM, DNZ, E, ERE, G, GAL, K, KW, LE, M, MHA, MPU, MW, SO, SOM, TBI. W, YALT) and more than 1500 specimens from 23 natural populations from Asia, the Caucasus, the Crimea, Bulgaria and the East European Plain. We determined leaf sh...