TY  - JOUR
A1  - Drenckhahn, Detlev
T1  - Neue und wieder entdeckte Hieracien auf Rügen
T1  - New taxa and rediscovered hawkweeds on the island of Rügen, Germany
N2  - The island of Rügen (Rugia), located in the Baltic sea, is the most northeastern (NE) part of Germany. Due to its particular geographic position at the border between scandinavian, middle european and continental european floral elements, Rügen harbours several hawkweed species (Hieracia) of the scandinavian area such as Hieracium fuscocinererum, H. subramosum, H. subrigidum and H. diaphanoides subsp. neoornatum and, at the same time, is the most northwestern location of H. echioides. Two endemic Hieracium species have been identified recently, i. e. H. muorum subsp. rugianum and H. caesium subsp. zabelianum (Gottschlich et al. 1998, Bot. Rundbr. Mecklenburg-Vorpommern 31:1-94). In the present communication, two further novel endemic Hieracium taxa will be described, which are restricted to the chalk cliffs of Cape Arkona and Jasmund, i. e. H. swantevitii and H. lachenalii subsp. litocretaceum. H. swantevitii (Swantevit’s hawkweed) is intermediate between H. caesium/H. bifidum and H. lachenalii with hairy, modestly glandular involucre and slightly serrated elongated leaves . This view of an intermediate position of H. swantevitii between these species was further supported by the ultrastructure of epidermal papillae of the outer bracts of the involucre visualized by scanning electron microscopy. H. lachenalii subsp. litocretaceum (chalk cliff hawkweed) is characterized by its narrow anguste to almost linear denticulate leaves in combination with mode rately glandular heads. In addition to the description of these two new hawkweed taxa , the rediscovery of three further species will be reported for Rügen, i. e. H. echioides (W. Gager in SE Rügen), H. cymosum subsp. cymosum (close to Göhren in SE Rügen) and H. subrigidum E Glowe in N Rügen. The locality of H. echioides appears to be most north-western site in middle Europe, the locality of H. cymosum is one of the last growth sites in the northern German lowlands and H. subrigidum (so far only known as a single herbarium specimen, collected 1858 in Rügen) has so far not been recorded in other localities of middle Europe.
KW  - Habichtskraut
KW  - Hieracium swantevitii
KW  - Hieracium lachenalii subsp. litocretaceum
KW  - Hieracium subrigidum
KW  - Hieracium cymosum
KW  - Hieracium echioides
KW  - Scanning electron microscopy
KW  - Epidermal papillae
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34843
ER  - 
TY  - JOUR
A1  - Gottschlich, Günter
A1  - Drenckhahn, Detlev
T1  - Iconography of the Genus Hieracium in central Europe - Part 1: General Description and Morphotypes
N2  - The genus Hieracium comprises more than one thousand sexual and apomictic species in Europe, with numerous intermediates and microspecies. Only a small fraction of the members of the genus Hieracium has been illustrated or photo-documented in the literature. Since many of these publications are difficult to obtain, only a few specialists are familiar with most of the species and subspecies described in the literature. In order to overcome this problem and encourage geobotanical research on the genus Hieracium, we decided to edit an iconography of central and southern European Hieracia in an electronical journal (Forum geobotanicum) with free international access through the internet. Part I of this endeavour contains descriptions and photographs of the morphological spectrum of the genus Hieracium. Here, we categorize the genus into 15 basic morphotypes. These types conform partly to the sections and subsections of the genus Hieracium, but are in some cases informal and may even include members of different sections. Classification of morphotypes is considered helpful to obtain a first rough picture of an unknown species that then can be traced to the species and subspecies level by using keys or, after completion of this iconography, simply by screening the relevant images. One particularly novel aspect of the present endeavour will be the regular inclusion of magnified images and scanning electron micrographs.
KW  - Habichtskraut
KW  - Hieracium
KW  - iconography
KW  - classification
KW  - scanning electron micrographs
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-35363
ER  -