@article{DrenckhahnWeber2020,
  author    = {Drenckhahn, Detlev and Weber, Heinrich E.},
  title     = {Die Nordfriesische Brombeere, Rubus boreofrisicus Drenckhahn \& H. E. Weber, eine endemische Rubus-Art der Westk{\"u}ste von Schleswig-Holstein, Deutschland},
  series = {Forum geobotanicum},
  volume    = {9},
  journal   = {Forum geobotanicum},
  issn      = {1867-9315},
  doi       = {10.3264/FG.2020.0116},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-198194},
  pages     = {66-69},
  year      = {2020},
  abstract  = {Rubus boreofrisicus Drenckhahn \& H. E.Weber ist eine bisher unbeschriebene Rubus-Art der Untergattung Rubus, Serie Discolores. Die Endbl{\"a}ttchen der 5-z{\"a}hligen, handf{\"o}rmigen Sch{\"o}sslingsbl{\"a}tter sind breit eif{\"o}rmig bis ann{\"a}hernd rund, unterseits grau-weißlich, oberseits dunkelgr{\"u}n und schwach behaart. Die Sch{\"o}sslinge sind braunrot, kantig bis schwach gefurcht, etwas behaart mit geraden bis schwach gekr{\"u}mmten, 5-8 mm langen, braunroten Stacheln mit heller Spitzenh{\"a}lfte. Die Bl{\"u}tenstiele besitzen Stieldr{\"u}sen. Rubus boreofrisicus kommt h{\"a}ufig im Waldg{\"u}rtel und in der angrenzenden D{\"u}nenheide der nordfriesischen Insel Amrum vor und ist auch 50 km s{\"u}dlich von Amrum in St. Peter-Ording im Westen der Halbinsel Eiderstedt vertreten.},
  subject      = {Rubus},
  language  = {de}
}
@misc{DunkelDrenckhahnZonneveld2022,
  author    = {Dunkel, Franz G. and Drenckhahn, Detlev and Zonneveld, Ben},
  title     = {Forum Geobotanicum 10 (2021/2022)},
  volume    = {10(2021/2022)},
  editor    = {Meierott, Lenz and Drenckhahn, Detlev and Dunkel, Franz G. and Ewald, J{\"o}rg and Fleischmann, Andreas},
  issn      = {1867-9315},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-298926},
  year      = {2022},
  abstract  = {Forum Geobotanicum is an electronic journal devoted to disseminate information concerning geographical distribution, ecology, morphology, taxonomy and conservation of vascular plants in the European Union with a main focus on middle Europe. It covers from molecular biology to environmental aspects. The focus is to publish original papers, reviews and announcements for the educated generalist as well as the specialist in this broad field. Forum Geobotanicum does not aim to supplant existing paper journals, but will be much more flexible in format, publication time and world-wide distribution than paper journals. Many important studies are being currently published in local journals and booklets and some of them are published privately. Hence, these studies will become aware to only a limited readership. Forum Geobotanicum will encourage authors of such papers to submit them as special issues of the journal. Moreover, the journal is planning to build up an E-mail-address section to support communication between geobotanists in Europe. The editors are optimistic that this electronic journal will develop to a widely used communication forum that will help to stimulate activities in the entire field of geobotany in middle Europe. To overcome problems of long term archivation and effective taxonomic publication of articles published electronically in Forum Geobotanicum, print versions of each volume of the journal and appropriate digital storage devices will be delivered freely to selected university libraries and state libraries in middle Europe.},
  subject      = {Geobotanik},
  language  = {de}
}
@misc{DrenckhahnEwaldHuebneretal.2004,
  author    = {Drenckhahn, Detlev and Ewald, J{\"o}rg and H{\"u}bner, Stefanie and Wissemann, Volker},
  title     = {Forum Geobotanicum Vol. 1 (2004)},
  volume    = {1(2004)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37927},
  year      = {2004},
  abstract  = {Forum geobotanicum ist eine elektronische Plattform, deren Zielsetzung darin besteht, neue Erkenntnisse der geobotanischen Forschung in der Europ{\"a}ischen Union mit Schwerpunkt Mitteleuropa umfassend zu verbreiten. Das Journal befasst sich mit allen Fragen von Verbreitung, {\"O}kologie, Morphologie und Taxonomie von Gef{\"a}ßpflanzen und soll das gesamte Spektrum der Geobotanik von molekularbiologischen Aspekten bis zu Umwelt- und Naturschutzfragen abdecken. Der Hauptfokus liegt auf der Publikation von Originaluntersuchungen und {\"U}bersichtsartikeln sowie Behandlung aktueller Fragen des Naturschutzes. Die Zielgruppen sind Personen mit Allgemeinkenntnissen in der Botanik und Floristik sowie Spezialisten auf den Gebieten der Geobotanik und Pflanzensystematik. Das Journal soll keine Zeitschrift in Druckform ersetzen, sondern eine Erg{\"a}nzung zu den traditionellen Publikationsorganen bilden. Der Vorteil der Zeitschrift liegt in ihrer Flexibilit{\"a}t und raschen Publikationszeit nach Begutachtung der eingereichten Manuskripte und den M{\"o}glichkeiten, in gr{\"o}ßerem Umfang Fotografien und andere Abbildungen zu ver{\"o}ffentlichen. Der Vorteil einer elektronischen Zeitschrift besteht weiterhin darin, dass die Ver{\"o}ffentlichungen weltweit jedermann sofort zug{\"a}nglich sind. Viele durchaus wichtige Untersuchungen aus dem Bereich der Geobotanik erscheinen in lokalen Publikationsorganen, wie Jahrb{\"u}chern und Heimatkalendern, oder auch im Eigenverlag. Da solche Ver{\"o}ffentlichungen bibliographisch kaum erfasst werden, k{\"o}nnen sie auch nicht in ad{\"a}quater Weise wahrgenommen werden. Forum geobotanicum soll erm{\"o}glichen, dass auch solche Publikationen in einer Literaturrubrik bekannt gemacht werden und ggf. nach Kl{\"a}rung von Copyright-Fragen als Supplemente der Zeitschrift ins Netz gestellt werden. Forum geobotanicum nutzt die Vorteile des Internets, indem es abrufbare Hilfen, wie ein Verzeichnis von Adressen, Pflanzenlisten etc. zur Verf{\"u}gung stellt. Insgesamt soll die Kommunikation zwischen Geobotanikern in Mitteleuropa erleichtert und eine Kommunikationsplattform etabliert werden, die die Aktivit{\"a}ten auf dem gesamten Wissenschaftsgebiet stimuliert. Das Journal ist uneigenn{\"u}tzig und f{\"u}r Autoren und Benutzer kostenfrei. F{\"u}r die Kostendeckung sind Sponsoren erw{\"u}nscht, denen eine begrenzte M{\"o}glichkeit zur Darstellung einger{\"a}umt werden kann. In der Anfangsphase wird das Journal von einem kleinen Herausgebergremiumbetrieben. Sollte sich Forum geobotanicum erfolgreich weiter entwickeln, ist an eine Erweiterung des Herausgebergremiums auf Experten aus allen Nationen des mitteleurop{\"a}ischen Raums gedacht. Um eine langfristige Verf{\"u}gbarkeit der Publikationen zu gew{\"a}hrleisten, wird jeder Jahrgang von Forum geobotanicum ausgedruckt, gebunden und mit CDs versehen an ausgew{\"a}hlte Universit{\"a}tsbibliotheken, Landes- und Staatsbibliotheken Deutschlands und wichtiger St{\"a}dte Mitteleuropas zur Archivierung und Ausleihe versandt.},
  subject      = {Geobotanik ; Pflanzengeographie},
  language  = {de}
}
@misc{DrenckhahnDrenckhahnWeberetal.2019,
  author    = {Drenckhahn, Detlev and Drenckhahn, Helga and Weber, Heinrich E. and Jansen, Werner and Weber, Heinrich E. and Zonnenveld, Ben J. M.},
  title     = {Forum Geobotanicum Vol. 8 (2018/2019)},
  volume    = {8(2018/2019)},
  editor    = {Meierott, Lenz and Drenckhahn, Detlev and Dunkel, Franz G. and Ewald, J{\"o}rg and Fleischmann, Andreas},
  issn      = {1867-9315},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175292},
  year      = {2019},
  abstract  = {Forum Geobotanicum is an electronic journal devoted to disseminate information concerning geographical distribution, ecology, morphology, taxonomy and conservation of vascular plants in the European Union with a main focus on middle Europe. It covers from molecular biology to environmental aspects. The focus is to publish original papers, reviews and announcements for the educated generalist as well as the specialist in this broad field. Forum Geobotanicum does not aim to supplant existing paper journals, but will be much more flexible in format, publication time and world-wide distribution than paper journals. Many important studies are being currently published in local journals and booklets and some of them are published privately. Hence, these studies will become aware to only a limited readership. Forum Geobotanicum will encourage authors of such papers to submit them as special issues of the journal. Moreover, the journal is planning to build up an E-mail-address section to support communication between geobotanists in Europe. The editors are optimistic that this electronic journal will develop to a widely used communication forum that will help to stimulate activities in the entire field of geobotany in middle Europe. To overcome problems of long term archivation and effective taxonomic publication of articles published electronically in Forum Geobotanicum, print versions of each volume of the journal and appropriate digital storage devices will be delivered freely to selected university libraries and state libraries in middle Europe.},
  subject      = {Geobotanik},
  language  = {de}
}
@misc{GottschlichDunkelDrenckhahnetal.2020,
  author    = {Gottschlich, G{\"u}nter and Dunkel, Franz G. and Drenckhahn, Detlev and Weber, Heinrich E. and Gallo, Lorenzo},
  title     = {Forum Geobotanicum Vol. 9 (2020)},
  volume    = {9(2020)},
  editor    = {Meierott, Lenz and Drenckhahn, Detlev and Dunkel, Franz G. and Ewald, J{\"o}rg and Fleischmann, Andreas},
  issn      = {1867-9315},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-298919},
  year      = {2020},
  abstract  = {Forum Geobotanicum is an electronic journal devoted to disseminate information concerning geographical distribution, ecology, morphology, taxonomy and conservation of vascular plants in the European Union with a main focus on middle Europe. It covers from molecular biology to environmental aspects. The focus is to publish original papers, reviews and announcements for the educated generalist as well as the specialist in this broad field. Forum Geobotanicum does not aim to supplant existing paper journals, but will be much more flexible in format, publication time and world-wide distribution than paper journals. Many important studies are being currently published in local journals and booklets and some of them are published privately. Hence, these studies will become aware to only a limited readership. Forum Geobotanicum will encourage authors of such papers to submit them as special issues of the journal. Moreover, the journal is planning to build up an E-mail-address section to support communication between geobotanists in Europe. The editors are optimistic that this electronic journal will develop to a widely used communication forum that will help to stimulate activities in the entire field of geobotany in middle Europe. To overcome problems of long term archivation and effective taxonomic publication of articles published electronically in Forum Geobotanicum, print versions of each volume of the journal and appropriate digital storage devices will be delivered freely to selected university libraries and state libraries in middle Europe.},
  subject      = {Geobotanik},
  language  = {de}
}
@article{GottschlichDrenckhahnMeierottetal.2023,
  author    = {Gottschlich, G{\"u}nter and Drenckhahn, Detlev and Meierott, Lenz and Zonneveld, Ben},
  title     = {Hieracium maculatum subsp. pseudogougetianum, eine neue Unterart aus dem Mainfr{\"a}nkischen Muschelkalkgebiet},
  series = {Forum Geobotanicum},
  volume    = {11},
  journal   = {Forum Geobotanicum},
  issn      = {1867-9315},
  doi       = {10.3264/FG.2023.0923},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-327601},
  pages     = {15-20},
  year      = {2023},
  abstract  = {In Lower Franconia/Northern Bavaria, a well-defined subspecies of the Hieracium maculatum group was detected. This subspecies is restricted to the slopes of the Main valley between W{\"u}rzburg and Hasloch with a hot spot (>90\% of total population) between the villages Th{\"u}ngersheim and Retzbach. Due to some similarities with H. glaucinum subsp. prasiophaeum (synonym: subsp. gougetianum) the subspecies is named H. maculatum subsp. pseudogougetianum. This subspecies grows preferentially on shell-bearing limestone gravels and begins flowering as early as mid-April. Head involucra are whitish hairy mixed with dark stalked glands. The basal leaf rosette consists of ovate to elliptic, toothed to serrate, dark spotted leaves, glabrous, glaucous above. Stems bear 1-3(4) stalked stem leaves and usually form long lateral flowering branches from the leaf axils. Like some other H. maculatum subspecies, H. maculatum subsp. pseudogougetianum is tetraploid with a mean genome weight (2C value) of 14.5 pg, distinguishing it from the H. glaucinum group, whose studied taxa are invariably triploid (mean 10.1 pg).},
  subject      = {Korbbl{\"u}tler},
  language  = {de}
}
@article{Drenckhahn2016,
  author    = {Drenckhahn, Detlev},
  title     = {Morphologie und Jahreszyklus von Ficaria calthifolia Rchb. - eine neu etablierte Sippe in Deutschland},
  series = {Forum Geobotanicum},
  volume    = {7},
  journal   = {Forum Geobotanicum},
  issn      = {1867-9315},
  doi       = {10.3264/FG.2016.0714},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136225},
  pages     = {1-17},
  year      = {2016},
  abstract  = {Ficaria calthifolia (diploide Form, Typ1) wurde k{\"u}rzlich nord-westlich des geschlossenen s{\"u}dosteurop{\"a}ischen Verbreitungsgebiet auch in Deutschland gefunden, n{\"a}mlich in W{\"u}rzburg (2006) und an Elbedeichen in Brandenburg (2014) und Sachsen (2015). Ficaria calthifolia ist durch das Fehlen von verl{\"a}ngerten mehrgliedrigen St{\"a}ngeln und die Abwesenheit von Brutknollen in den Blattachseln gekennzeichnet. Die 1-2 (3) St{\"a}ngel von Ficaria calthifolia verbleiben {\"u}berwiegend im Boden (hypog{\"a}isch), k{\"o}nnen aber im Laufe der Anthese aus dem Boden hervorwachsen. Die gestielten Laubbl{\"a}tter setzen sich aus Grundbl{\"a}ttern und einer Rosette von bis zu 8 St{\"a}ngelbl{\"a}ttern pro St{\"a}ngel zusammen. Letztere entspringen aus dem terminalen St{\"a}ngelknoten (St{\"a}ngelblatt-rosette). In W{\"u}rzburg kommen zwei Populationen von Ficaria calthifolia vor, diploide Typ1-Pflanzen und triploide Typ2-Pflanzen. Letztere sind robuster, besitzen gr{\"o}ßere Bl{\"u}ten (bis 4 cm) und entwickeln nur vereinzelte reife N{\"u}sschen. Pflanzen mit h{\"o}herem Ploidiegrad (wahrscheinlich pentaploid, Typ3) wurden auch gefunden. Etwa 60\% der 3 bis 8 Bl{\"u}tenstiele von Typ1-Pflanzen besitzt kein St{\"a}ngelblatt, der Rest einen Knoten mit 1 bis 2 (3) Hochbl{\"a}ttern. Die Zahl der Kronbl{\"a}tter betr{\"a}gt 8 (vereinzelt 9), die durchschnittliche Zahl reifer, eif{\"o}rmiger N{\"u}sschen pro Fruchtstand betr{\"a}gt 7 (W{\"u}rzburg) / 14 (Elbe) (maximal 26). Aus vom Rhizom abgebrochenen und im Mai gepflanzten Speicherknollen keimten im Sp{\"a}therbst desselben Jahrs neue Pflanzen. Der Jahreszyklus des Wurzelsystems wird beschrieben. Durch spontane Abl{\"o}sungen einzelner Speicherknollen findet eine vegetative Vermehrung statt. Neben N{\"u}sschen w{\"a}ren abgebrochene Speicherknollen f{\"u}r die Fernansiedlung der Sippe an Elbe (u.a. Verschleppung durch Hochwasser) und Main (Verschleppung durch Schiffe und andere Vektoren) ausreichend.},
  subject      = {Karyotyp},
  language  = {de}
}
@article{DrenckhahnGottschlichZonneveld2023,
  author    = {Drenckhahn, Detlev and Gottschlich, G{\"u}nter and Zonneveld, Ben},
  title     = {Neubeschreibungen und 2C-Werte von Pilosella macranthela subsp. silvae-pici (Spessart-Mausohrhabichtskraut) und Pilosella ottonis (Otto-Mausohrhabichtskraut) mit einer {\"U}bersicht {\"u}ber das Vorkommen von P. macranthela-Taxa in Bayern.},
  series = {Forum Geobotanicum},
  volume    = {11},
  journal   = {Forum Geobotanicum},
  issn      = {1867-9315},
  doi       = {10.3264/FG.2023.1114},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-344797},
  pages     = {21-34},
  year      = {2023},
  abstract  = {A pentaploid taxon from the Pilosella macranthela group was discovered in Lower Franconia/Bavaria which is newly described here as P. macranthela subsp. sylvae-pici. It grows mainly in the Bavarian Bunter Spessart and occurs with three small, isolated stands also in the limestone area of the Main valley and Tauber area. Its habit of growth is intermediate between the furcata and laxicephala types of Pilosellae with epigeal and partly hypogeal stolons and a tendency to form clusters. The upper and lower surfaces of the rosette leaves have stellate hairs. The peduncles and the phyllaries are densely covered with dark glandular hairs with yellowish glandular heads. The lateral teeth of the ligules often are separated by incisions. A tetra- und pentaploid transitional taxon between P. macranthela subsp. sylvae-pici and P. officinarum is described as P. ottonis. P. ottonis is tetra- and pentaploid with up to 7 capitula. It is densely covered with dark stalk glands on phyllaries and resembles forms of P. acutifolia in habit. The phyllaries of P. ottonis are covered with numerous epidermal papillae with a diameter of about 10-20 μm and in this aspect resemble P. macranthela subsp. sylvae-pici and P. glomerata. However, in P. officinarum epidermal papillae are absent. Plants of genetically heterogeneous tetra- and heptaploid P. macranthela have been found outside the Spessart as spontaneous hybrids between P. glomerata and P. officinarum and also occur sporadically without P. glomerata in the vicinity.},
  subject      = {Habichtskraut},
  language  = {de}
}
@article{Drenckhahn2004,
  author    = {Drenckhahn, Detlev},
  title     = {Neue und wieder entdeckte Hieracien auf R{\"u}gen},
  doi       = {10.3264/FG.2004.0127},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34843},
  year      = {2004},
  abstract  = {The island of R{\"u}gen (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, R{\"u}gen 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 R{\"u}gen, i. e. H. echioides (W. Gager in SE R{\"u}gen), H. cymosum subsp. cymosum (close to G{\"o}hren in SE R{\"u}gen) and H. subrigidum E Glowe in N R{\"u}gen. 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 R{\"u}gen) has so far not been recorded in other localities of middle Europe.},
  subject      = {Habichtskraut},
  language  = {de}
}
@article{DrenckhahnZonneveld2022,
  author    = {Drenckhahn, Detlev and Zonneveld, Ben},
  title     = {Rubus admirabilis Drenckhahn, eine neue Brombeerart aus dem Formenkreis der Serie Vestiti an der Westk{\"u}ste von Schleswig-Holstein, Deutschland},
  series = {Forum Geobotanicum},
  volume    = {10},
  journal   = {Forum Geobotanicum},
  issn      = {1867-9315},
  doi       = {10.3264/FG.2022.1228},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-298658},
  pages     = {38-44},
  year      = {2022},
  abstract  = {Rubus admirabilis Drenckhahn is a tetraploid new species of the Rubus section Rubus, series Vestiti. Stem leaves are 5-foliolate, digitate to weakly pedate with elongated, obovate acuminate terminal leaflets, adpressed hairy upper side and light green shimmering, softly hairy under side. Stems are arching (up to 2 m) partly climbing, obtuse-angled, densely hairy and glandular, gray green to dull brown, armed with 10(3-21) /5cm straight slender prickles, mostly 30-45º declining, 4.6(3-7)mm long. Pedicles of inflorescence are densely hairy (patent and partly adpressed), armed with 2-4 (per cm) slender patent to slightly curved prickles (1-2 mm long) and studded with numerous stalked glands (0.3-0.5 mm long) and some bristles. The species tolerates shadow and prefers moist soil. The type locality is probably the species' site of introduction or genesis. It is located west of the town Garding on the North Frisian peninsula of Eiderstedt (several hundred shrubs), where several non-native Rubus species were probably introduced in the course of reforestation in 1970. Rubus admirabilis spreads south to the town of Heide in Dithmarschen and north to the island of Amrum (maximal range diameter of 70 km) and seems to be in an expansive phase.},
  subject      = {Brombeere},
  language  = {de}
}