The complete chloroplast genome assembly of Commelina caroliniana Walter (Commelinaceae).

We sequenced and published the chloroplast genome of Commelina caroliniana Walter, which was previously misidentified as C. diffusa owing to their morphological similarities until 1989. The genome of C. caroliniana is 160,857 bp long [large single copy region: 88,064 bp; a small single copy region: 18,549 bp; two inverted repeat regions: 27,122 bp] and has a GC content of 35.7%. The genome comprises 133 genes, including 87 coding sequences (CDSs), 38 tRNAs, and eight rRNAs. The phylogenetic relationship between C. caroliniana and related species was analyzed using the maximum likelihood method based on the 79 CDSs of the chloroplast genome. Phylogenetic analysis revealed that C. caroliniana is closely related to C. communis. Our findings will contribute to studies on species identification and phylogenetic and evolutionary research. These results enhance our understanding of the Commelina genus.

Comparative analysis of the complete chloroplast genome of Papaveraceae to identify rearrangements within the Corydalis chloroplast genome.

Chloroplast genomes are valuable for inferring evolutionary relationships. We report the complete chloroplast genomes of 36 Corydalis spp. and one Fumaria species. We compared these genomes with 22 other taxa and investigated the genome structure, gene content, and evolutionary dynamics of the chloroplast genomes of 58 species, explored the structure, size, repeat sequences, and divergent hotspots of these genomes, conducted phylogenetic analysis, and identified nine types of chloroplast genome structures among Corydalis spp. The ndh gene family suffered inversion and rearrangement or was lost or pseudogenized throughout the chloroplast genomes of various Corydalis species. Analysis of five protein-coding genes revealed simple sequence repeats and repetitive sequences that can be potential molecular markers for species identification. Phylogenetic analysis revealed three subgenera in Corydalis. Subgenera Cremnocapnos and Sophorocapnos represented the Type 2 and 3 genome structures, respectively. Subgenus Corydalis included all types except type 3, suggesting that chloroplast genome structural diversity increased during its differentiation. Despite the explosive diversification of this subgenus, most endemic species collected from the Korean Peninsula shared only one type of genome structure, suggesting recent divergence. These findings will greatly improve our understanding of the chloroplast genome of Corydalis and may help develop effective molecular markers.

Taxonomic relevance of petiole anatomical and micro-morphological characteristics of Clematis L. (Ranunculaceae) taxa from South Korea.

We assessed the micro-morphological and anatomical structures of the petioles of 19 Clematis taxa from South Korea. The petiole surface features were observed with the help of stereomicroscopy and scanning electron microscopy, and the anatomical features are studied via microtomy and light microscopy. The results of this study showed that the presence/absence and abundance of trichomes, petiole cross-section outlines, upper surface wings and grooves, and the number of vascular bundles were useful for species discrimination in Clematis. Among the studied taxa, C. hexapetala was the only species with a glabrous petiole surface. Two types of trichomes were observed in the other 18 taxa: long, non-glandular and flagelliform trichomes and short, glandular capitate trichomes. We found four to six major vascular bundles and a maximum of eight interfascicular vascular bundles (C. heracleifolia and C. urticifolia) in the 19 taxa. A cluster analysis based on UPGMA identified six clusters with 18 nodes. Although the number of taxa investigated was limited, taxa from the sections Tubulosae, Viorna, and Astragene clustered with each other in the UPGMA phenogram due to the overall similarity of petiole features. Based on this observation, we can conclude that most of the petiole features are limited to the species level, and thus, the data obtained could be used as descriptive and/or diagnostic features for particular taxa, which may be useful for the investigation of problematic taxa in the genus.

Complete chloroplast genome of Clematis taeguensis (Ranunculaceae), an endemic species from South Korea.

The complete chloroplast (cp) genome sequence of Clematis taeguensis Y.N.Lee (Ranunculaceae) was determined to be 159,534 bp in length, consisting of large (79,326 bp) and small (18,338 bp) single-copy regions and a pair of identical inverted repeats (30,935 bp). The genome contains 92 protein-coding genes, 32 tRNA genes, 8 rRNA genes, and 1 pseudogene (infA). Phylogenetic analysis of 19 taxa inferred from the chloroplast genome showed a relationship with C. taeguensis, which is also recognized as a species endemic to the Korean Peninsula. The complete cp genome sequence of C. taeguensis reported here provides important information for future phylogenetic and evolutionary studies in Ranunculaceae.

Achene Morphology and Anatomy of Clematis L. (Ranunculaceae) in Korea and Its Taxonomic Implications.

Clematis, a widely distributed genus in Ranunculaceae, is one of the most difficult groups of taxa in the family from a taxonomic point of view. A comprehensive study on achene morphology and the anatomy of 19 taxa of Clematis from Korea was carried out using scanning electron and light microscopy to evaluate the taxonomic significance of achene characters. Clematis achenes are elliptical, obovate or fusiform in shape, light yellow or brown to black in color and completely or sparsely covered with hairs. The permanent style is elongated and plumose in all the studied taxa except C. brachyura. We found that the size, indument, permanent style, surface sculpture, shape in cross-section, and nature and thickness of the exocarp, and endocarp were valuable achene features for species delimitation and may contribute to the unraveling of the taxonomic problems in the genus Clematis. One-way analysis of variance (ANOVA) indicated that the quantitative achene variables among the species were highly significant (p < 0.001). Principal component analyses based on seven quantitative characters and UPGMA (unweighted pair-group method with arithmetic mean) analysis based on seven quantitative and 18 qualitative characters also signify the utility of achene features for taxonomic discriminations of the Clematis taxa within the genus. Similar to other morphological characters in the genus Clematis, achene morphological and anatomical characters with the limited taxonomic value alone cannot be expected to resolve the infrageneric relationships but certain achene features combined with other morphological features could be useful as an alternative means of determining the infrageneric relationships within the genus.

Comparative wood anatomy of Korean Viburnum L. (Adoxaceae) and its taxonomic implication.

Comparative wood anatomy of Viburnum was carried out to understand the differences in wood features amongst the species which might be useful for taxonomic discrimination in the genus. Altogether, nine taxa belonging to five clades were investigated using a sliding microtome and light microscopy. The growth rings are well represented and earlywood and latewood are distinguishable in cross-section. Some of the important wood features include angular, oval and rounded vessels with scalariform perforation plates, opposite to scalariform inter-vessel pitting, rounded pits with slit-like apertures, thick-walled xylem tracheids with simple, rounded bordered pits, diffuse axial parenchyma, uni- and multiseriate rays, 2-4 cells wide. In general, there is a remarkable uniformity in the qualitative wood features in Viburnum species, although quantitative measurement showed some disparities. The most significant quantitative wood variables which might be useful for taxonomic groupings of the species comprise a frequency of vessels and rays, the diameter of the vessels and tracheids in the radial and tangential planes and height and width of rays in the tangential plane.