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Jochen Heinrichs:

A taxonomic revision of Plagiochila sect. Hylacoetes, sect. Adiantoideae and sect. Fuscoluteae in the Neotropics with a preliminary subdivision of Neotropical Plagiochilaceae into nine lineages

2002. 184 pages, 2 tables, 58 plates, 14x23cm, 510 g
Language: English

(Bryophytorum Bibliotheca, Band 58)

ISBN 978-3-443-62030-1, paperback, price: 70.00 €

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Keywords

bryophytePlagiochilaHylacoeteAdiantoideaeFuscoluteaeNeotropicsNeotropical Plagiochila

Contents

Synopsis top ↑

Currently, 20 section and subsection names are in use for Neotropical Plagiochilae. Phylogenetic analyses of morphological and phytochemical characters as well as of sequence variations of internal transcribed spacer regions of nuclear ribosomal DNA reveal the presence of only 9 monophyletic lineages of Plagiochila (Dumort.) Dumort. in the Neotropics, assignable to the sections Adiantoideae Lindenb., Alternantes Carl, Arrectae Carl, Cucullatae Schiffn., Fuscoluteae Carl, Glaucescentes Carl, Hylacoetes Carl, Rutilantes Carl, and Vagae Lindenb.
The illegitime Plagiochila sect. Superbae Carl, which was erected for some of the largest Neotropical species of Plagiochila, disintegrates into P. sect. Hylacoetes and P. sect. Adiantoideae. Members of sect. Hylacoetes are characterized by a capsule wall epidermis without thickenings on the walls and usually fan-shaped, terminal androecia. In contrast, sect. Adiantoideae has a capsule wall epidermis with nodulose cell wall thickenings and simple, intercalary androecia. Sect. Adiantoideae comprises 4 species and is restricted to the Neotropics. Sixteen species (including the new Plagiochila patriciae J .Heinrichs & H. Anton) are recognized within sect. Hylacoetes, which occurs not only in the Neotropics but also in Africa (P. boryana Gottsche ex Steph.). The monospecific genera Szweykowskia Gradst. & M.Reiner and Steereochila Inoue are treated as members of the latter section; Steereochila ecuadorica Inoue is lowered to a variety of P. dimorpha Lindenb. & Gottsche.
All 8 species of Plagiochila sect. Fuscoluteae (syn. nov.: P. sect. Bursatae Carl) are characterized by the presence of surface wax. The section is restricted to the Neotropics, with the exception of P. heterophylla Lindenb. ex Lehm., which also occurs in Atlantic Europe, were it was known as P. atlantica F .Rose.
Keys to the members of Plagiochila sect. Adiantoideae, Hylacoetes and Fuscoluteae are given and descriptions of gametophytic and sporophytic features as well as distributional and ecological data are provided.

Rev.: Nova Hedwigia vol. 76, no. 1-, pp. 269-271 top ↑

The genus Plagiochila, with more than 1600 published binomials and about 400 to 450 species worldwide, belongs to one of the largest genera of the hepatics. The rather monotonous morphology and high plasticity especially of leaf cell patterns, leaf dentation, leaf position, and leaf shape causes great problems in identifying the species, and several attempts have been done, to subclassify the genus. Even the most comprehensive classification by Carl (1931) remains provisional, causing great confusion. A world-wide approach therefore is urgently required for understanding this large and difficult genus and its allies.

Jochen Heinrichs from Göttingen started with this huge and nearly insoluble task, revising as a first step the neotropical Plagiochila species. Nearly 850 taxa are described from tropical America, that in his opinion may belong to 100-120 species. In the present work, a taxonomic revision of Plagiochila sect. Hylacoetes, sect. Adian- thoideae and sect. Fuscoluteae is presented, including a new classification of the group into nine monophyletic lineages. The study is based on molecular data (nrITS region), new morphological characters (e.g., capsul wall epidermis, oil bodies, surface waxes) and chemical investigations.

After an introduction and historical part, material & methods (phytochemistry, DNA extraction, PCR amplification, sequencing, selection of characters), the morphology and anatomy (stem structure and branching, leaves, underleaves, oil bodies, asexual reproduction, androecia, gynoecia, sporophyte, spores and elaters) are described. All taxonomic characters employed are treated in detail. Following is the phylogeny and sectional classification in nine lineages based on nrITS sequences of 38 species. These nine lineages are supported by high bootstrap percentage values, often assignable to morphological and phytochemical defined sections. Also problems were not ignored: e.g., the problems of intra-individual ITS polymorphism, as demonstrated for vascular plants, or interspecific hybridization and reticulate evolutionary phenomens are discussed, that makes a general applicability of the ITS region for phylogenetic analysis problematical. The first part of the study is finished by an overview and description of these nine sections, including the differentiating characters in tabular form.

The main part of the book is the taxonomic treatment of the three independant lineages assignable to sect. Hylacoetes, sect. Adianthoideae, and sect. Fuscoluteae. The main diagnostic characters of these are:

P. sect. Hylacoetes: characterized by the absence of surface wax, a capsule wall epidermis without thickenings on the cell walls and usually fan-shaped terminal androecia with bracts not overlaping dorsally. This section comprises 18 species, among them the former monospecific genera Szweykowskia and Steereochila, that clearly nested in the molecular analysis within the P. sect. Hylacoetes clade.

P. sect. Adianthoideae: characterized by the absence of surface wax, a capsule wall epidermis with thickenings on the cell walls and simple, intercalary androecia with bracts overlaping dorsally. Here, four species are included.

P. sect. Fuscoluteae: characterized by the presence of surface wax, a capsule wall epidermis with thickenings on the cell walls and simple, intercalary androecia with bracts not overlaping dorsally. This section comprises nine species.

Within each section a dichotomous key is given and each species is fully described. As might be expected, many species have an extensive synonymy. The detailed specific descriptions of the gametophyte and sporophyte are accompanyied by line drawings of all, but one species (P. rudischusteri; 46 plates), citation of representative specimens examined, distributional and ecological notes. The descriptions and illustrations are very good and serves its purpose well. Highly welcome are the remarks on differentiation and variation of the species. Beside one new species, P. patriciae from Costa Rica, the study includes three new combinations [comb. & stat. nov.: P. dimorpha var. ecuadorica (= Steereochila ecuadorica), P. superba var. macrotricha (= P. macrotricha), and P. heterophylla var. beauverdii (= P. beauverdii)] and about 77 taxa are brought to synonymy. 12 plates based on SEM studies of surface wax structures, spores and elaters add to the excellent overall impression. Up to now, 60 Neotropical Plagiochila species can be differentiated, which represent about half of the expected number of species. The present treatment includes 31.

As a further main result of the study, P. sect. Subplanae now is treated as a synonym of the former palaeotropical section Cucullatae, due to the similarities in morphology (capsule wall structure) and the molecular analysis. This leads to a range extension of this section to the Neotropics. Its single representant in the Neotropics is P. subplana.

Revising a notoriously difficult genus such as Plagiochila is certainly no piece of cake. It seems to me, that Heinrich has done a very good work and progressing well in revising neotropical Plagiochilas. With this excellent, thoroughness and com- prehensiness account on the neotropical species, Heinrichs therefore fills a huge gap. But the work has also shown, that natural groups (monophyletic lineages) of neotropical Plagiochilas often have no autapomorphisms. Therefore they can be identified only on the basis of tendencies of characters. Absolute diagnostic characters are infrequent. The quality of a revision must be measured by the working ability of the identification keys. I was not able to test the keys completely, but I have the feeling, that the identification of neotropical Plagiochilas will be not easy, also in future. Nevertheless, this revision is urgently needed and is a must for bryologists, especially those working in the Neotropics.

HARALD KÜRSCHNER, Berlin

Nova Hedwigia vol. 76, no. 1-, pp. 269-271

Bespr.: Cryptogamie, Bryologie 2002, 24 (1) top ↑

Les analyses phylogénétiques des caractères morphologiques et phytochimiques aussi bien que celles des variations séquentielles des régions ITS de l'ADN ribosomal du noyau révèlent la présence de 9 lignées monophylétiques de Plagiochila (Dumort.) Dumort. des Néotropiques, assignables aux sect. Adiantoideae Lindenb., Alternantes Carl, Arrectae Carl, Cucullatae Schiffn., Fuscoluteae Carl, Glaucescentes Carl., Hylacoetes Carl, Rutilantes Carl. et Vagae Lindenb.

Les espèces de la sect. Superbae Carl. illeg. sont réparties dans les sections Hylacoetes et Adiantoideae. Les membres de la sect. Hylacoetes sont caractérisés par un épiderme pariétal de la capsule sans épaississement des parois, et avec des androécies terminales, habituellement en éventail ; ceux de la sect. Andiantoideae ont un épiderme pariétal de la capsule avec des épaississements des parois cellulaires noduleux et des androécies simples et intercalées ; ceux de la sect. Fuscoluteae ont une cire de surface. Des clés aux membres des trois sections sont données.

Chaque taxon est décrit (gamétophyte et sporophyte) et illustré, accompagné de données de distribution et d'écologie.

La sect. Adiantoideae comprend 4 espèces restreintes aux Néotropiques. La sect. Hylacoetes comporte seize espèces (dont P. patriciae sp. nov. ) qui ne sont pas restreintes aux seuls Néotropiques. La sect. Fuscoluteae (P. Sect. Bursatae Carl, syn. nov. ) inclut 8 espèces res- treintes aux Néotropiques à l'exception de P. heterophylla Lindenb. ex Lehm. présente en Europe atlantique sous le nom de P. atlantica F. Rose. Les excellents dessins au trait des différentes espèces, les très bonnes photographies au microscope électronique à balayage du sporoderme, des spores et des élatères forment une très utile illustration à ce travail minutieux de synthèse d'un genre d'hépatique très complexe.

En appendices : les spécimens étudiés pour telle ou telle technique, les caractères utilisés pour le traitement cladistique. Bibliographie, pp. 166-178 ; index des noms, pp. 179-184.

Cryptogamie, Bryologie 2002, 24 (1)

Contents top ↑

Abstract 7
Introduction 8
Acknowledgements 10
History 10
Materials and methods 13
Morphological studies 13
Typification and species concept 13
Phytochemistry 14
DNAextraction 15
PCR amplification, cloning and sequencing 15
Phylogenetic analyses 16
Phylogenetic analysis of morphological and phytochemical characters:
selection of characters, ingroup and outgroup species 17
Phylogenetic analyses of the nrITS 1 -5.8S-ITS2 region 19
Morphology and anatomy 20
Size, growth form and habit 20
Stem structure and branching 20
Leaves 22
Oil bodies 26
Underleaves 27
Asexual reproduction 27
Androecia 28
Gynoecia 28
Sporophyte 30
Spores and elaters 31
Chemistry and chromosome numbers 33
Phylogeny and sectional classification of Neotropical Plagiochila,
with particular consideration of the Adiantoideae (Fuscoluteae)
Superhae - complex 34
Phylogeny of Plagiochila in the Neotropics, based on morphology and
photochemistry 34
Phylogeny of Plagiochila in the Neotropics, based on variation of
nrITS sequences 38
nrITS sequence variation and monophyly of the species 41
The Adiartoideae (Fuscoluteae) Superbae complex 42
Molecular evidence for the occurrence of the Paleotropical Plagiochila sect.
Cucullatue in the Neotropics 44
Plagiochila sect. Vagae and sect. Glaucescentes 45
Plagiochila sect. Carringtoniae 46
Monophyly of Plagiochila sect. Plagiochila and sect. Alternantes is not
supported by the molecular investigation 46
Plagiochila sect. Rutilantes and sect. Arrectue 47
Hierarchical subdivision of Plagiochila is not supported by the molecular
investigation 48
Problems of the nrITS region as a Phylogenetic informative marker 49
Preliminary notes on the remaining Neotropical genera of
Plagiochilaceae 50
Preliminary overview of the Neotropical sections of Plagiochila 51

Taxonomic treatment 61
Plagiochila sect. Hylacoetes Carl 66
Plagiochila amicta Steph. 68
Plagiochila boryana Gottsche ex Steph. 72
Plagiochila breuteliana Lindenb. 75
Plagiochila canelensis Steph. 80

Plagiochila cacullifolia Jack & Steph. 83
Plagiochila dimorpha Lindenb. & Gottsche var. dimorpha 85
Plagiochila dimorpha var. ecuadorica (Inoue) J.Heinrichs, comb. et
stat. nov 87
Plagiochila dominicensis Taylor 90
Plagiochila ensiformis Taylor 93
Plagiochila flabelliflora Steph. 96
Plaglochila guevarii H.Rob 98
Plagiochila husnotii Steph. lOO
Plagiochila macrostachya Lindenb. 103
Plagiochila patriciae J.Heinrichs & H.Anton spec. nov 107
Plagiochila superba (Nees ex Spreng.) Mont. & Nees var. superba 110
Plagiochila superba var. macrotricha (Spruce) J.Heinrichs, comb. et
stat. nov 114
Plagiochila turgida Herzog 116
Plagiochila vincentina Lindenb. 119
Plagiochila sect. Adiantoideae Lindenb. 123
Plagiochila adiantoides (Sw.) Lindenb. 123
Plagiochila cristata (Sw.) Lindenb. 128
Plagiochila grandicrista Steph. 131
Plagiochila herminieri Steph. 133
Plagiochila sect. Fuscoluteae Carl 135
Plagiochila aerea Taylor 136
Plagiochila fuscolutea Taylor 141
Plagiochila heterophylla Lindenb.. ex Lehm. var. heterophylla 145
Plagiochila heterophylla var. beauverdii (Steph..) J.Heinrichs,
comb. et stat. nov. 148
Plagiochila longiramea Steph. 151
Plagiochilaparaphyllina Herzog 153
Plagiochilarudischusteri H.Rob 155
Plagiochila subbidentata Taylor 157
Plagiochila tabinensis Steph. 160
Excludenda 162
Nominadubia 166
References 166
Index of names 179