Botanical Journal of the Linnean Sociey

Gil-Amaya, Karen; Fernández, Melania; Oses, Lizbeth; Benavides-Acevedo, Miguel; Grimaldi, David; Blanco, Mario A; Karremans, Adam P

doi: 10.1093/botlinnean/boae054pmid: N/A

Pleurothallidinae is the most diverse Neotropical subtribe in Orchidaceae and is almost exclusively pollinated by insects of the order Diptera. Dracula, a genus of 138 species in the Pleurothallidinae, is known to attract Zygothrica (Drosophilidae) flies, common macrofungi visitors, by imitating fungal volatile compounds and lamellae. Interestingly, Dracula orchids do not appear to offer any rewards to their floral visitors. While brood-site imitation of macrofungi has been suggested as their pollination system, the exact behaviour of flies during their extended visits to the orchid flowers has yet to be confirmed. In this study, we document the pollination mechanism of Dracula erythrochaete. We characterize the floral structures involved in the mechanism using anatomical and morphological evidence. Additionally, through in situ observations and camera recordings, we describe the insect behaviour. We show that flowers of D. erythrochaete share the same group of visitors as nearby macrofungi, including different Zygothrica species, seven of which were determined as effective pollinators. Male and female flies were attracted to the flowers and displayed feeding behaviour. Accordingly, proteins were detected in high concentrations on the papillae at the base of the movable lip and in papillary trichomes of the sepals, near the column. The concept of brood-site imitation is debated, as no oviposition events were observed and no eggs were found on the flowers. Therefore, a mixed strategy of congregation/brood-site imitation and food reward is proposed for pollination.

Calevo, Jacopo; Viruel, Juan; Adamo, Martino; Bersweden, Leif; Gargiulo, Roberta; Cowan, Robyn S; Fay, Michael F

doi: 10.1093/botlinnean/boae050pmid: N/A

Low-coverage sequencing in plants allows whole plastomes to be obtained that can be used to investigate phylogenetic relationships among groups. The genus Orchis (c. 20 species), is usually divided into Orchis subgenera Orchis and Masculae. These subgenera are composed of three (Anthropophorae, Italicae, and Orchis) and four (Masculae, Provinciales, Pusillae, and Robustocalcare) sections, respectively. In this study, we used genome-skimming data to assemble the plastid genomes of 11 species (15 accessions) of Orchis, representing six out of the seven sections, from which we constructed a dated phylogenetic tree. Results suggest that the divergence between the subgenera occurred c. 10.53 Mya, whereas the main separation of the sections is dated between 6.53 and 3.48 Mya. Furthermore, we found 206 (in O. anthropophora) to 230 (in O. provincialis) microsatellite regions in the assembled plastomes, which could be used to design specific primers for further population genetics and phylogenetic studies and, ultimately, inform conservation efforts. The plastome data here presented represent a new contribution to the molecular systematics of the genus, and they can be used to further explore infrageneric and infrascpecific molecular variation in Orchis.

Guerreiro, Carolina; Brignone, Nicolás F; Clark, Lynn G; Vega, Andrea S

doi: 10.1093/botlinnean/boae048pmid: N/A

We performed a phylogenetic analysis with estimated clade ages and an ancestral-range estimation focused on the Patagonian species of Chusquea, i.e. the Chusquea culeou clade, to unravel their biogeographical history. Phylogenetic analyses were conducted with sequence data from four plastid markers, using maximum parsimony and Bayesian inference approaches. The complete sampling and addition of the Patagonian Chusquea species into a phylogenetic framework revealed the most likely origin and evolutionary history of the Chusquea culeou clade. The Patagonian Chusquea originated roughly 11.35 Mya, most likely from a common ancestor from the Atlantic Forest region, when this lineage underwent in situ diversification and its species evolved sympatrically. All the extant species have arisen in the last 8 Myr. Moreover, according to the present sampling, the most recent common ancestor of subtribe Chusqueinae originated in the Northern Andes, which is also the most common source area of the estimated dispersal events. Some other preliminary insights on the biogeographic history of the genus are included.

Morales-Alonso, Ana; Muñoz-Schüler, Paulo; Pereira-Silva, Luciana; Donadío, Sabina; Martín-Bravo, Santiago; Jiménez-Mejías, Pedro

doi: 10.1093/botlinnean/boae038pmid: N/A

This is the second study of a series of thorough studies into the taxonomy and systematics of Carex in South America. Here, we present the systematic placement, taxonomic account, formal typifications, and summarized distributions for the 31 accepted South America species of Carex subg. Psyllophorae, all belonging to sect. Junciformes. We have conducted an exhaustive revision of literature, more than 400 specimens from 32 South and North American and European herbaria have been studied, and a Sanger phylogenetic study with four DNA regions and morphometric analyses for the C. phalaroides group have been performed. We present an enlarged phylogenetic study where sect. Junciformes sampling has increased by 11 species regarding previous studies, only lacking four species of the group (C. herba-alpacae, C. moorei, C. nelmesiana, and C. transandina). South American species of sect. Junciformes are grouped into four major lineages: C. camptoglochin Clade, Aciculares Clade (South America and Australia–New Zealand), C. phalaroides group, and Junciformes Clade. We have resolved the C. phalaroides complex into six independent species with a clear geographic structure. We successfully unravelled the systematic placement of three species included here for the first time (C. boelckeiana, C. reicheana, and C. manuelbarrosii). An identification key is provided for the studied species. We propose 30 new typifications, and four new species are described (C. herba-alpacae, C. manuelbarrosii, C. melliza, and C. via-montana).

Filin, Vladimir R; Platonova, Anna G

doi: 10.1093/botlinnean/boae052pmid: N/A

The tapetum is an important tissue in the sporangia of tracheophytes that provides nutrition for developing spores and participates in sporoderm construction, but the data on the tapetum in the sporangia of bryophytes and, in particular, hornworts, are contradictory. Some investigators considered the capsule wall and pseudoelates a tapetum in hornworts, but others suppose that the tapetum is absent in hornwort capsules at all. The structure of the sporocytes and spores, pseudoelaters, the lining layer of the capsule wall, and the outer layer of the columella of Phaeoceros laevis were studied at successive developmental stages by light, fluorescence, and transmission electron microscopy. We revealed that sporocytes accumulate carbohydrates that are required for the construction of the sporoderm and the storage of nutrients in mature spores before the formation of a special wall. Such a feature significantly distinguishes hornworts from mosses and angiosperms. Pseudoelaterocytes and pseudoelaters do not possess any ultrastructural features, indicating that they provide the sporocytes and spores with nutrition. Cells of the lining layer of the capsule wall and the outer layer of the columella do not possess characteristic ultrastructural features of secretory tissue at any developmental stage (in contrast to the moss tapetum), but they apparently participate in the transfer of nutrients in the capsule locule from the foot at the time the sporocytes are actively growing and accumulating nutrients. We accept the strict interpretation of the tapetum as a tissue that lines the capsule locule and has the specialized ultrastructure characteristic of the secretory tissues. Therefore, contrary to the opinion of some researchers, we believe that neither pseudoelaters nor the lining layer of the capsule wall should be considered a tapetum. Columella cells have a structural specialization for upward transport of assimilates, and they should not be regarded as a tapetum. We suppose that tapetum was absent in the common ancestor of the hornworts as well as in the common ancestor of embryophytes.

Dosil Hiriart, Florencia D; Hernández, Marcelo P; Segura, Luciano N; Katinas, Liliana

doi: 10.1093/botlinnean/boae051pmid: N/A

Myxodiaspory, the extrusion of sticky substances by the diaspores (seeds, fruits, anthocarps, and parts of infrutescences), has several selective advantages, one of which is aiding the adherence of diaspores between feathers/fur of animals that transport them over short or long distances. The diaspores of Asteraceae have three structures that can contain sticky substances: exocarp epidermal cells, exocarp trichomes, and viscid pappus. The South American species Adenostemma brasilianum (Asteraceae) has all three features. We examined the anatomy, secreted substances, and mode of adhesion of the diaspores of A. brasilianum to understand its strategies for dispersion. The fruit comprises an exocarp with glandular trichomes arranged spirally and scarce nonglandular trichomes, two layers of mesocarp separated by phytomelanin, and an endocarp. The pappus has a basal ring, a stalk, and a head with glandular trichomes. The mucilage, secreted by the glandular trichomes of fruit and pappus, reacted positively to tests for pectins, essential oils, lipophilic substances, and gums. The test for tannins gave a homogeneous positive reaction in the phytomelanin area, and as droplets, in the outer mesocarp layer and in the exocarp. The whole capitulum of A. brasilianum is adapted for successful transportation of its diaspores via diaspore release, secretion, and positioning. We discuss the idea that the dispersal adaptive traits found here evolved as phylogenetic parallelisms in the family.

Sultan, Amir; Khan, Nazar; Kljuykov, Eugene; Khan, Amjad; Samigullin, Tahir; Lyskov, Dmitry

doi: 10.1093/botlinnean/boae053pmid: N/A

The tribe Komarovieae (Apiaceae) comprises 13 species distributed in Central Asia, Northeastern Iran, Afghanistan, India, Nepal, and southwest, central, and eastern China. The clade includes eight genera (six of them are monotypic), which bear a lot of apomorphic features and have very few common characters. Our morphological and molecular studies have shown that enigmatic Afghan monotypic genus Mastigosciadium is also a part of Komarovieae, despite critical morphological uniqueness even to this group. In addition, a new genus and species, endemic to Zhob district of Pakistan is described and illustrated. The new taxon is recognized by molecular phylogenetic analysis of nrITS and rps16 as a part of Komarovieae. Common morphological features for the species of Komarovieae are provided. After review, the clade comprises 10 genera and 15 species.