Henk Groth

Cryptic speciation in Herbertus (Herbertaceae, Jungermanniopsida): Range and morphology of Herbertus sendtneri inferred from nrITS sequences

Abstract.Maximum likelihood and parsimony analyses of nrITS1-5.8S-ITS2 sequences place Austrian Herbertus sendtneri in a well bootstrap supported clade with Herbertus azoricus and Neotropical accessions which were alternatively assigned to Herbertus subdentatus or Herbertus dicranus. Asian and African Herbertus dicranus form a separate lineage which is placed sister to several European Herbertus taxa. Herbertus borealis from the British Isles is placed sister to H. stramineus in a robust sister relationship, indicating that the species does not belong in the synonymy of H. dicranus. As a result of the molecular investigation, the range of Herbertus sendtneri is extended to the Neotropics and H. azoricus is placed into the synonymy of H. sendtneri. Without much doubt, Herbertusdicranus does not occur in tropical America. Morphologically, H. sendtneri and H. dicranus can at most be separated by weak tendencies. Herbertus sendtneri is characterized by the frequent occurrence of coarse appendages at the leaf margins and often completely papillose leaves. H. dicranus often has small appendages and a nearly smooth basal leaf half. Herbertus borealis, which is nonmonophyletic with H. dicranus in the molecular trees, cannot be separated morphologically from forms of H. dicranus with small appendages. Herbertus subdentatus is not identical with H. sendtneri. Morphological homoplasy and cryptic speciation are obviously common in Herbertus.

Goodbye or welcome Gondwana? – insights into the phylogenetic biogeography of the leafy liverwort Plagiochila with a description of Proskauera, gen. nov. (Plagiochilaceae, Jungermanniales)

Molecular phylogenies based on chloroplast gene rps4 sequences and nuclear ribosomal ITS sequences have been generated to investigate relationships among species and putative segregates in Plagiochila (Plagiochilaceae), the largest genus of leafy liverworts. About a fourth of the ca. 450 accepted binomials of Plagiochilaceae are included in these phylogenetic analyses, several represented by multiple accessions. A clade with Chiastocaulon, Pedinophyllum, and Plagiochilion is placed sister to a clade with numerous accessions of Plagiochila. Plagiochila pleurata and P. fruticella are resolved sister to the remainder of Plagiochilaceae and transferred to the new Australasian genus Proskauera which differs from all other Plagiochilaceae by the occurrence of spherical leaf papillae. The historical biogeography of Plagiochilaceae is explored based on the reconstructions of the phylogeny, biogeographic patterns and diversification time estimates. The results indicate that the current distribution of Plagiochilaceae cannot be explained exclusively by Gondwanan vicariance. A more feasible explanation of the range is a combination of short distance dispersal, rare long distance dispersal events, extinction, recolonization and diversification.

Origin and subdivision of Plagiochila (Jungermanniidae: Plagiochilaceae) in tropical Africa based on evidence from nuclear and chloroplast DNA sequences and morphology

Maximum likelihood analyses based on the internal transcribed spacer region of nuclear ribosomal DNA and the chloroplast protein coding gene rps4 were conducted to investigate phylogenetic relationships among species of Plagiochila and to reconstruct the ranges of natural species groups within the genus. Based on the results of the molecular analyses and on morphological evidence, the tropical African species of Plagiochila are assigned to the sections Arrectae, Cucullatae, Hylacoetes, Rutilantes, Vagae, and the new sect. Africanae (P. barteri, P. colorans). With the exception of Africanae, all sections possess intercontinental ranges; their centers of diversity are in the tropics. Clade and species diversity in Africa is lower than in other parts of the tropics and may reflect drought periods of the Pleistocene. Intercontinental ranges at specific level exist between tropical America and Africa whereas similarities between tropical Asia and Africa were only recovered at the sectional level. ITS sequence sets were used to test the monophyly of species with intercontinental ranges and to explore the-development of the Afro-American range of P. boryana. A well supported clade with accessions of P. boryana from Bolivia and Uganda is nested in the robust neotropical Hylacoetes. This topology and the low genetic distance of the different P. boryana accessions provide some evidence for long-range dispersal of P. horyana eastwards across the Atlantic, originating from the Neotropics. An African origin of the Vagae clade which includes neotropical and paleotropical taxa is suggested by the clustering of accessions from the East African Islands at the base of this clade. In addition, the presented data support the hypothesis of several switches from Africa to Asia and vice versa. A derived clade within Vagae includes accessions from the African mainland and the Neotropics. Our results seem to indicate that the extant tropical African Plagiochila flora is a mixture of old elements and rather recent immigrants.

Molecular, morphological, and phytochemical evidence for a broad species concept of Plagiochila bifaria (Hepaticae)

Abstract Debate over the synonymy of the European Plagiochila killarniensis and the Neotropical P. bifaria of P. sect. Arrectae has focused on differences in secondary metabolite composition. The broad morphological species concept of P. bifaria proposed in recent papers has now been tested by comparing nrDNA ITS1 and ITS2 sequences of P. bifaria populations encompassing several different morpho- and chemotypes from the British Isles, Tenerife, Costa Rica, Brazil, Ecuador, and Bolivia, with sequences of other species of P. sects. Arrectae, Rutilantes, and Fuscoluteae. Phylogenetic analyses demonstrate that specimens of P. bifaria form a well supported clade within Plagiochila sect. Arrectae. Sequences of P. bifaria from the British Isles, Tenerife, and Ecuador, representing the “methyl everninate” chemotype, form a well supported subclade within the P. bifaria clade. Sequences of specimens from Costa Rica, Brazil, and Bolivia are placed in the basal part of the P. bifaria clade. The data support a broad species concept of P. bifaria. The different chemotypes do not warrant distinct taxonomic ranks. Plagiochila centrifuga and P. compressula are treated as new synonyms of P. bifaria.

Phytochemical, morphological, and molecular evidence for the occurrence of the neotropical liverwort Plagiochila stricta in the Canary Islands, new to Macaronesia

Abstract Plant material from the Canary Islands similar to Plagiochila spinulosa (Dicks.) Dumort. has been identified as the Neotropical liverwort P. stricta Lindenb. The secondary metabolite profiles of CDCl3 extracts of both Neotropical and Macaronesian specimens of P. stricta are distinct from those of P. spinulosa in containing alloocimene and neoalloocimene as the principal monoterpenes rather than β-phellandrene; the two species also show differences in the 9,10-dihydrophenanthrenes and other aromatic compounds present. Phylogenetic analyses of ITS nrDNA sequence variation place P. spinulosa sister to P. stricta. Morphologically, P. stricta from Tenerife is distinguished most easily from P. spinulosa by the scarcely decurrent antical leaf margin.

Plagiochila cucullifolia var. anomala var. nov. from Ecuador, with notes on discordant molecular and morphological variation in Plagiochila

Abstract.Plagiochila cucullifolia Jack & Steph. var. anomala J. Heinrichs & Gradst. var. nov. is described and illustrated. The new variety is known from a single locality in southern Ecuador and differs from P. cucullifolia var. cucullifolia by the flat, not saccate leaves, somewhat smaller plant size and weaker leaf dentation. According to phylogenetic analyses of 35 nrDNA ITS1 and ITS2 sequences of Plagiochila, the two varieties of P. cucullifolia form a monophyletic lineage and are placed in a well supported clade together with five other species of Plagiochila sect. Hylacoetes: P. dimorpha Lindenb. & Gottsche var. ecuadorica (Inoue) J. Heinrichs, P. flabelliflora Steph., P. patriciae J. Heinrichs & H. Anton, P. macrostachya Lindenb. and P. turgida Herzog. Within Plagiochila, nrITS sequence variation is not concordant with morphological diversification. ITS sequences of Plagiochila cucullifolia s.str. and of P. dimorpha var. ecuadorica differ in only 23 aligned positions whereas two sequences of P. subplana Lindenb. differ in 86 aligned positions. Morphologically, P. cucullifolia s.str. and P. dimorpha var. ecuadorica differ in more than 20 characters and previously these two taxa were placed in separate genera. P. subplana phenotypes show considerable variation in leaf shape and dentation but the extremes are linked by numerous intermediates.

Plagiochila virginica A. Evans rather than P-dubia Lindenb. & Gottsche occurs in Macaronesia; placement in sect. Contiguae Carl is supported by ITS sequences of nuclear ribosomal DNA

Abstract. Plagiochila dubia Lindenb. & Gottsche is reduced to a synonym of the Neotropical P. patula (Sw.) Lindenb. Specimens from the Canary Islands and Madeira proved to belong to the eastern North American P. virginica A.Evans, new to Europe. Phylogenetic analyses of the internal transcribed spacer regions (ITS1-5.8S-ITS2) of nuclear ribosomal DNA of ten Plagiochila species produced four independent lineages that are well supported by all bootstrap analyses (maximum likelihood, maximum parsimony, and distance). These lineages correspond with the Plagiochila sections Arrectae, Contiguae, Cucullatae and Glaucescentes. Spruces “Ramiflorae” and “Cauliflorae” may no longer be regarded as monophyletic units of Plagiochila.

Plagiochila rutilans (Hepaticae): A Poorly Known Species from Tropical America

Abstract The neotropical liverwort, Plagiochila rutilans Lindenb., is conspecific with P. remotifolia Hampe & Gottsche, P. farlowii Steph., P. harrisana Steph, and P. organensis Herzog. Plagiochila standleyi Carl is reduced to a variety of P. rutilans. Plagiochila gymnocalycina (Lehm. & Lindenb.) Mont. and P. portoricensis Hampe & Gottsche (= P. simplex (Sw.) Lindenb.) are excluded from the synonymy of P. rutilans. Plagiochila rutilans var. liebmanniana Gottsche is a synonym of P. crispabilis Lindenb.; P. rutilans var. laxa Lindenb. and var. angustifolia Herzog are conspecific with P. gymnocalycina. Sporophytes of P. rutilans are described for the first time. Fresh material of P. rutilans exhibits a distinct odor of peppermint caused by the presence of several menthane monoterpenoids, principally pulegone. NMR (nuclear magnetic resonance) fingerprints and GC-MS data indicate that the lipophilic secondary metabolite profiles are distinct for the two varieties accepted in this study.

Reinstatement of Plagiochila maderensis (Jungermanniopsida : Plagiochilaceae) based on chemical evidence and nrDNA ITS sequences

Abstract Plagiochila maderensis Gottsche ex Steph. is reinstated as a Madeiran endemic. This taxon was synonymized with P. spinulosa (Dicks.) Dumort. over 35 years ago and has been accepted under that name in recent years. Morphologically, P. maderensis, which is known only in the sterile state, differs from P. spinulosa in having a smooth leaf surface, larger leaf cells and an often broadly truncate leaf apex. Phytochemical analysis using NMR and GC–MS profiling demonstrated that the lipophilic secondary metabolites are strikingly and unambiguously distinct from those of P. spinulosa. The dominant constituent is 4-hydroxy-3’-methoxybibenzyl, present in exceptionally large amounts. Analysis of the ITS region of nrDNA of P. maderensis and incorporation of the sequence into a maximum likelihood analysis of a dataset comprising another 28 Plagiochila and two outgroup sequences revealed that P. maderensis is a member of Plagiochila sect. Rutilantes Carl. Plagiochila maderensis is placed sister to the Neotropical species P. gymnocalycina (Lehm. & Lindenb.) Mont. and P. trichostoma Gottsche, but in a clade that does not have bootstrap support. It is known already that 4-hydroxy-3’-methoxybibenzyl is the principal bibenzyl constituent of P. trichostoma and chemical analysis has now shown that this applies also to P. gymnocalycina.

Different Fates of Two Mitochondrial Gene Spacers in Early Land Plant Evolution

Plant mitochondrial DNA is generally characterized by slow sequence drift but frequent genomic recombination. Accordingly, gene sequences in plant mitochondria are informative for old cladogenic events, whereas intergenic regions have so far not been considered for phylogenetic reconstruction because high recombinational activity rearranges mitochondrial gene orders too frequently. Here we report that an ancient gene continuity, the nad5‐nad4‐nad2 gene arrangement, is conserved among the bryophyte lineages: mosses, liverworts, and hornworts. The nad4‐nad2 spacer is surprisingly conserved at a size of only 26 bp in all three bryophyte lineages. In striking contrast, the small ancestral nad5‐nad4 spacer, of only 57 bp in the alga Chara, is significantly increased in size, to about 600 bp in mosses and 1000–1300 bp in liverworts, and even exceeds 3000 bp in hornworts. A large group II intron fragment and a nad6 pseudogene sequence, respectively, contribute to the expanded spacer sizes in liverworts and in hornworts. The small nad4‐nad2 intergenic region is retained in the lycophyte Isoetes lacustris, whereas no linkage between nad5 and nad4 could be detected in this quillwort. Given its size and sequence variability, the intergenic region between nad5 and nad4 holds promise as a locus for phylogenetic analyses within the bryophyte lineages.