[Show abstract][Hide abstract] ABSTRACT: Database of published chromosome numbers and ploidy-level estimates of the tribe Alysseae is presented, together with the revised generic concept and the list of accepted names, to reflect the most recent taxonomic and phylogenetic studies in Alysseae. It is available on-line at www.alysseae.sav.sk. The tribe encompasses 24 genera and 277 species. Chromosome numbers and/or ploidy levels are known for 171 out of 297 recognized taxa. Of these, 95 (55.6 %) taxa are diploids, 43 (25.1 %) are polyploids, and 33 (19.3 %) involve both diploids and polyploids. The most common base chromosome number in the tribe is x = 8 and less frequent is x = 7. The highest variation in base chromosome numbers (x = 7, 8, 11, 15) is found in the genus Hormathophylla. A key to all genera and descriptions of the two new genera Cuprella and Resetnikia are presented. Many new nomenclatural combinations, mainly in the re-established Odontarrhena (77), are proposed.
Full-text · Article · Dec 2015 · Plant Systematics and Evolution
[Show abstract][Hide abstract] ABSTRACT: The genus Boechera is one of the most difficult species complexes in North America, with about 70 sexual diploids and hundreds of apomictic taxa representing diverse combinations of nearly every known sexual genome. In this study, we set out to clarify the taxonomy of Boechera lignifera, which currently includes a small number of sexual diploid populations in addition to the widespread apomictic diploid upon which the name is based. Using data from cytological studies, microsatellite DNA analyses, geography, and morphology, we demonstrate that the apomictic populations are genetically quite divergent from the sexual diploids. We propose the name Boechera kelseyana to accommodate the sexual diploid taxon, which occurs entirely south of the geographic range of B. lignifera. Boechera kelseyana is consistently separable from B. lignifera based on pollen and seed morphology, the length and proximal orientation of fruiting pedicels, differences in the branching and orientation of trichomes on the lowers stems, and the number of flowers and cauline leaves on unbranched fertile stems.
Full-text · Article · Dec 2015 · Systematic Botany
[Show abstract][Hide abstract] ABSTRACT: Draba laegaardii Al-Shehbaz (Brassicaceae), a new species from Cotopaxi (Ecuador), is described and illustrated. It is readily disinguished from the related D. hemsleyana Gilg by having erect and self-supporting stems, densely overlapping ciliate leaves, 24- to 28-ovuled ovaries, and linear-lanceolate to lanceolate fruits 1.2-1.8 cm with a distinct midvein. The diversity of Draba L. and its distribution in South American countries are briefly discussed.
No preview · Article · Dec 2015 · Novon A Journal for Botanical Nomenclature
[Show abstract][Hide abstract] ABSTRACT: Cardamine xinfenii, a new species from southern Sichuan Province, is described and illustrated. It does not seem to be closely related to any of the known Asian species of the genus. It is easily distinguished by the scapose habit and by having slender stolons, 7–9-foliolate, strongly toothed basal leaves, spreading floral parts, and filiform, non-auriculate cauline leaves (bracts) subtending the base of lowermost 1 or 2 pedicels of the raceme.
No preview · Article · Dec 2015 · Harvard Papers in Botany
[Show abstract][Hide abstract] ABSTRACT: Brassicaceae is one of the most diverse and economically valuable angiosperm families with widely cultivated vegetable crops and scientifically important model plants, such as Arabidopsis thaliana. The evolutionary history, ecological, morphological and genetic diversity and abundant resources and knowledge of Brassicaceae make it an excellent model family for evolutionary studies. Recent phylogenetic analyses of the family revealed three major lineages (I, II, and III), but relationships among and within these lineages remain largely unclear. Here, we present a highly supported phylogeny with six major clades using nuclear markers from newly sequenced transcriptomes of 32 Brassicaceae species and large datasets from additional taxa for a total of 55 species spanning 29 out of 50 tribes. Clade A consisting of Lineage I and Macropodium nivale is sister to combined Clade B (with Lineage II and others) and a new Clade C. The ABC clade is sister to Clade D with species previously weakly associated with Lineage II and Clade E (Lineage III) is sister to the ABCD clade. Clade F (the tribe Aethionemeae) is sister to the remainder of the entire family. Molecular clock estimation reveals an early radiation of major clades near or shortly after the Eocene-Oligocene boundary and subsequent nested divergences of several tribes of the previously polytomous Expanded Lineage II. Reconstruction of ancestral morphological states during the Brassicaceae evolution indicates prevalent parallel (convergent) evolution of several traits over deep times across the entire family. These results form a foundation for future evolutionary analyses of structures and functions across Brassicaceae.
Full-text · Article · Oct 2015 · Molecular Biology and Evolution
[Show abstract][Hide abstract] ABSTRACT: Aubrieta ekimii, a new species from Kocaeli
Province (Turkey), is described and illustrated, and its relationship
to putatively closest relatives, A. olympica and A.
pinardii, is discussed. Scanning electron microscopy micrographs
of the indumentum of A. ekimii and its relatives are
presented. Cytology, ecology, conservation status, and geographical
distribution of the novelty and related species are
presented. The knowledge database BrassiBase (http://bras
sibase.cos.uni-heidelberg.de/index.php) is shown herein as a
powerful tool to recognize potentially new species. DNA
sequence data from the transcribed spacers of nuclear encoded
ribosomal RNA (ITS1 and ITS2) was subjected to the
respective phylogenetic placement algorithm in BrassiBase
and, after adding further sequence information from the
plastid trnLF region, tribal-wide phylogenetic analyses were
conducted to confirm the systematic placement of the novelty.
Because of limited DNA sequence variation, we did not
obtain a highly resolved phylogenetic hypothesis of Aubrieta.
Our study further highlights Anatolia as a craddle of species
diversity with many overlooked and undescribed species.
Full-text · Article · Oct 2015 · Plant Systematics and Evolution
[Show abstract][Hide abstract] ABSTRACT: The new species Eutrema racemosum is described, and its relationship to the closely related E. heterophyllum and E. edwardsii are discussed based on morphological, cytological, and molecular data. The novelty differs from E. heterophyllum by having elongated racemes and from E. edwardsii by somewhat reflexed fruiting pedicels. Four chloroplast DNA fragments and nuclear ITS region were sequenced for multiple individuals of each species. Three species show distinct and stable sequence variations. Eutrema racemosum and E. heterophyllum form a clade sister to that of E. edwardsii in phylogenetic analyses of sequence variations. Our cytological studies revealed that E. heterophyllum is a diploid with the small genome size, while E. racemosum is a tetraploid with duplicate genomes. These available data support the recognition of E. racemosum as a distinct species well differentiated morphologically and genetically, as well as well-isolated reproductively from its sister species E. heterophyllum. We further found some interspecific triploid hybrids between tetraploid E. racemosum and diploid E. heterophyllum, which seem to be sterile according to our germination experiments.
[Show abstract][Hide abstract] ABSTRACT: Species delimitation is fundamental to the basic understanding of biodiversity because of the central role that the concept of species plays in most branches of biology. However, few studies have been designed to test conflicting delineations of plant species under an integrated species concept using DNA barcodes in combination with other lines of evidence. Such an approach may deliver more objective, testable and uniform species units as subjects for a range of studies. Here we aim to examine competing hypotheses of species delimitation in Orychophragmus, a member of the mustard family, based on these methods and principles. Two to seven species have previously been recognized in this genus by different taxonomists. We sequenced five commonly used DNA barcodes (nuclear ribosomal ITS and chloroplast matK, rbcL, trnH-psbA, and trnL-F) for 160 individuals collected across the major distribution ranges of all taxa currently recognized in the genus. Based on the monophyletic clusters produced by analysis of the combined nrITS and cpDNA sequence variations, we recovered nine independent evolutionary lineages that were further supported by diagnosable morphological traits, distinct inter-cluster genetic gaps, reproductive isolation, and geographical distribution. These lineages may be treated as nine species. We also found substantial differences in the capacity of nrITS and cpDNA barcodes to discriminate between closely related species in two clades of the genus. Our empirical study of Orychophragmus highlights the importance of applying both chloroplast DNA and nrITS barcodes for species delimitation in plants.
[Show abstract][Hide abstract] ABSTRACT: Ricotia (Brassicaceae) is a genus of nine species endemic to the eastern Mediterranean region. Its phylogenetic relationships, monophyly, and tribal placement have not yet been adequately addressed. To achieve this, sequence data from the nuclear-encoded ribosomal internal transcribed spacer (ITS) and chloroplast DNA (trnL-F region) were analysed by parsimony, maximum likelihood, and Bayesian methods for 45 Ricotia accessions, representing all species and covering their entire distribution ranges, along with outgroups of selected members of main Brassicaceae lineages and tribes. The results clearly indicate, with high posterior probability/bootstrap support, that Ricotia is monophyletic and together with Lunaria should be assigned, with Biscutella and Megadenia, to tribe Biscutelleae. Divergence time estimations, using both a secondary calibration approach and published ITS substitution rates, indicate that the origin of Ricotia (crown group age, 9.2–11.3 Ma) predates the onset of the Mediterranean climate after the Messinian Salinity Crisis (5.9–5.3 Ma). We tentatively conclude that diversification within Ricotia was affected by climate changes during that geological epoch which had a great impact on the speciation history of the Mediterranean flora and fauna. Ancestral area reconstruction analyses revealed that Mediterranean Ricotia species arose in southwest Anatolia (likely Antalya region), whereas the origin of the genus remained unclear. Finally, a perennial life cycle appears to be ancestral in Ricotia, as revealed by an ancestral character state reconstruction analysis.
[Show abstract][Hide abstract] ABSTRACT: Abstract— Hybrid speciation is relatively common in plants compared to other well-studied groups. Polyploidy and apomixis are strongly associated with hybrid speciation, presumably due to the opportunities they provide for both reestablishing reproductive function in hybrids with incomplete chromosomal homology and creating rapid reproductive isolation in sympatry. Boechera, a species-rich genus closely related to Arabidopsis, is a particularly fertile ground for the study of hybrid speciation. Thirty-eight apomictic triploid hybrid species are currently recognized in Boechera. Recent research has shown that apomictic diploid hybrids, although very rare in angiosperms, are common in Boechera. Given this complexity, focused studies of individual species complexes are critical to understanding speciation and diagnosing biodiversity in Boechera. Here we analyze DNA sequences from seven nuclear loci and multilocus genotypes from 15 microsatellite markers in a group of closely related taxa formerly included in B. fendleri. Our results support the recognition of four species previously segregated from B. fendleri s. l., including three genetically distinct, sexual diploids (B. fendleri, B. spatifolia, and B. texana) and one apomictic triploid hybrid (B. porphyrea). We also identify four novel apomictic diploid hybrid species ( B. carrizozoensis , B. centrifendleri , B. sanluisensis , and B. zephyra ) and additional apomictic triploid hybrids. Our results reveal a complex network of relationships. Sexual diploid species can hybridize to form apomictic diploids, and members of these two groups can hybridize to form trigenomic, apomictic triploids.
Full-text · Article · Aug 2015 · Systematic Botany
[Show abstract][Hide abstract] ABSTRACT: Englerocharis blanca-leoniae is described and illustrated, and its relationship to the closely related E. peruviana is discussed. As a result, Englerocharis now includes five species, all except the latter are narrowly endemic to Peru and known from single collections. The generic limit is expanded to accommodate the new species, and a key to the five known species of the genus is presented.
No preview · Article · Jun 2015 · Harvard Papers in Botany
[Show abstract][Hide abstract] ABSTRACT: Weberbauera incisa Al-Shehbaz, P. Gonzáles & A. Cano (Brassicaceae), a new species from southern Peru, is described and illustrated. It differs from the closely related W. spathulifolia (A. Gray) O. E. Schulz by being completely glabrous and by having incised leaves, flattened and papery petioles of basal leaves, and torulose fruits.
Full-text · Article · Jun 2015 · Novon A Journal for Botanical Nomenclature
[Show abstract][Hide abstract] ABSTRACT: The type status of 146 names of Himalayan taxa is discussed, of which the lectotypes of 133 names are designated here for the first time, including a few that were incompletely lectotypified due to the existence of more than one sheet in the institution where the type was said to be. These 133 species and infraspecfic names were originally described in the genera Arabis (15), Chorispora (4), Cochlearia (4), Dilophia (2), Draba (64), Ermania (2), Erysimum (5), Eutrema (4), Nasturtium (3), Sisymbrium (9), and Thlaspi (2). In addition, lectotypes are designated for one name each in the 15 other genera: Barbarea, Brassica, Capsella, Cardamine, Cheiranthus, Dipoma, Goldbachia, Hemilophia, Hutchinsia, Lepidostemon, Martinella, Megacarpaea, Microsisymbrium, Sinapis, and Sophiopsis. The type status of 13 additional names in Arabis (1), Buchingera (1), Draba (8), Erysimum (2), Parlatoria (1), Parrya (2), Sisymbrium (1), and Torularia (1) are discussed.
No preview · Article · Jun 2015 · Harvard Papers in Botany
[Show abstract][Hide abstract] ABSTRACT: Lectotypes of twenty-eight names of taxa currently recognized or synonymized in Cardamine are designated as part of the work on the account of the genus for the Pan-Himalayan Flora. Among them, the previous first-step lectotypification of the name Cardamine
calthifolia is finalized. In cases when specimen images are available online, stable identifiers for specimens, other permanent links, or links via JSTOR Global Plants are provided.
[Show abstract][Hide abstract] ABSTRACT: Xerodraba is a South American genus distributed exclusively in the Andean-Patagonian region of southern Argentina and Chile. It is characterized by forming cushions with imbricate, scalelike leaves and solitary, terminal flowers. An updated taxonomic revision of the genus based on morphological analyses using both qualitative and quantitative characters is presented here. Xerodraba currently includes five species distributed in Argentina, of which two also grow in Chile. Xerodraba pectinata is reduced to synonymy of X. lycopodioydes, and X. pycnophylloides is treated as a subspecies of X. patagonica. The new combination X. patagonica subsp. pycnophylloides is proposed. Descriptions, keys to all taxa, updated geographical distributions, maps, and illustrations are provided.
[Show abstract][Hide abstract] ABSTRACT: The new species Aphragmus pygmaeus Al-Shehbaz (Sichuan) and Cardamine pseudotrifoliolata Al-Shehbaz (Xizang or Tibet) are described and illustrated. Their distinguishing characters from the respectively nearest relatives A. oxycarpus (Hook. f. & Thomson) Jafri and C. trifoliolata Hook. f. & Thomson are discussed.
No preview · Article · May 2015 · Novon A Journal for Botanical Nomenclature
[Show abstract][Hide abstract] ABSTRACT: Cardamine hongdeyuana, a Tibetan endemic, is described and illustrated. Its distinguishing characters from the nearest relative C. yunnanensis are discussed. A brief note of the diversity of Cardamine in China is given.