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Premise The cactus family (Cactaceae) is a speciose lineage with an almost entirely New World distribution. The genus Eulychnia with eight currently recognized species is endemic to the Atacama and Peruvian Deserts. Here we investigated the phylogeny of this group based on a complete taxon sampling to elucidate species delimitation and biogeographic history of the genus. Methods A family-wide Bayesian molecular clock dating based on plastid sequence data was conducted to estimate the age of Eulychnia and its divergence from its sister genus Austrocactus. A second data set obtained from genotyping by sequencing (GBS) was analyzed, using the family-wide age estimate as a secondary calibration to date the GBS phylogeny using a penalized likelihood approach. Ancestral ranges were inferred employing the dispersal extinction cladogenesis approach. Results Our GBS phylogeny of Eulychnia was fully resolved with high support values nearly throughout the phylogeny. The split from Austrocactus occurred in the late Miocene, and Eulychnia diversified during the early Quaternary. Three lineages were retrieved: Eulychnia ritteri from Peru is sister to all Chilean species, which in turn fall into two sister clades of three and four species, respectively. Diversification in the Chilean clades started in the early Pleistocene. Eulychnia likely originated at the coastal range of its distribution and colonized inland locations several times. Conclusions Diversification of Eulychnia during the Pleistocene coincides with long periods of hyperaridity alternated with pluvial phases. Hyperaridity caused habitat fragmentation, ultimately leading to speciation and resulting in the current allopatric distribution of taxa.

Eulychnia: —The genus includes two main clades according to Larridon et al. (2018) and Merklinger et al. (2021). The two groups are morphologically and phylogenetically supported and clearly associated with geographical changes in the Atacama Desert (a proposed key is reported below). According to the results of the phylogenetic analyses three former species-complexes were resolved: Eulychnia acida Phil., E. breviflora Phil., and E. iquiquensis (K.Schum.) Britton & Rose. 1. Ribs steep and narrow; flowers and fruits densely covered with wool; perianth segments lanceolate (“ breviflora -group”)............2 - Ribs broad and flattened; flowers and fruits with less and shorter wool; perianth segments spathulate (“ acida -group”)................6 2. Spines numerous, central ones very long; seed large.................................................................................................. 3. E. breviflora - Spines less numerous and shorter; seed smaller.................................................................................................................................3 3. Pulp orange; areoles with long wool; plants low to medium-sized....................................................................................................4 - Pulp whitish; areoles with shorter wool; plants higher......................................................................................................................5 4. Plants shrubby; branches sub-prostrate, thin........................................................................................................... 2. E. barquitensis - Plants arborescent; branches ascending, thicker..................................................................................................... 7. E. saint-pieana 5. Areoles far apart, wool dark brown........................................................................................................................... 8. E. taltalensis - Areoles closely set, wool greyish............................................................................................................................. 6. E. iquiquensis 6. Flower and fruit areoles spiny....................................................................................................................................... 4. E. castanea - Flower and fruit areoles spineless......................................................................................................................................................7 7. Plants shrubby; branches (sub)prostrate with superior portions pointing upwards; ribs 8–12...........................................................8 - Plants arborescent; branches ascending to erect; ribs up to 16.......................................................................................... 1. E. acida 8. Shrubs low; branches thin, grey-green; flowers with short wool; new areoles with abundant white felt................ 5. E. chorosensis - Shrubs higher; branches thicker, yellowish-green; flowers with in conspicuous hairs; areoles with short grey felt.......................................................................................................................................................................................................... 9. E. vallenarensis

Populations of the columnar cactus genus Eulychnia (Cactaceae) are an iconic sight in the Chilean Atacama Desert. The most recent taxonomic treatment of the genus suggested to accept up to seven ta...

Betalains occur only in few plant families of order Caryophyllales where they found vital constituents in edible parts of plants usually in leaves, flowers, and stems. They also occur in some fungi of higher order like in the fly agaric (A. muscaria) and some genera of Basidiomycetes. Red beetroots (B. vulgaris), cacti fruits belonging to the genus Opuntia (mainly Opuntia ficus-indica), the dragon fruits of Hylocereus cacti (mainly Hylocereus polyrhizus), and the Swiss chard (B. vulgaris) are the known edible sources of betacyanins and betaxanthin. The less common edible sources are Ulluco tubers (Ullucus tuberosus), fruits and berries of Eulychnia cacti, and Rivina humilis. It is a class of yellow and red indole-derived pigments which replace anthocyanin pigments in plants and are mainly responsible for coloration, but their role in fungi is unknown. Betalain accumulation occurs in cell vacuoles synthesized mainly in epidermal and subepidermal plant tissues due to their hydrophilicity.

Summary 1. Epiphytes have the potential to modify the canopy environments in which they grow. Accurately evaluating the impact of epiphytes can be challenging, since plants without epiphytes may also otherwise differ from host plants, and experimental removal is impractical and difficult to replicate in many forests. 2. We studied the impacts of epiphytes (primarily fruticose lichens and Tillandsia spp.) on host plants (Eulychnia saint-pieana and Caesalpinia spinosa) in two fog ecosystems in Chile (Pan de Azucar) and Peru (Atiquipa). These desert ecosystems sustain very high epiphyte loads and depend heavily on fog-water inputs. Using a combination of artificial substrates and epiphyte removals, we show significant impacts of epiphytes on their host plants. 3. The presence of epiphytes reduced throughfall volumes, reducing fog and rainfall inputs to the soil beneath host plant canopies. 4. Soil moisture loss rate was increased below cacti after removal of epiphytes from sun-facing but not shade-facing branches. This suggests epiphyte effects on hosts are microclimatic. 5. Epiphytes also buffered temperature fluctuations and reduced daytime vapour pressure deficit. 6. Epiphytes can have strong effects on host plant ecophysiology and forest ecosystem processes, making them an important component for models and studies of canopy environments.

The taxonomy of Chilean Cactaceae is notoriously difficult (see e.g., Duarte et al. 2014). Molecular data, and phylogenetic approaches, provided answer to better understand the natural classification of cacti (see e.g., Nyffeler 2002, Edwards 2005, Nyffeler & Eggli 2010, Ritz et al. 2012, Schlumpberger & Renner 2012, Larridon et al. 2015, 2018). As part of an ongoing revision of the Chilean Cacti, which is part of the “Modern Flora of Chile” initiative, nomenclatural novelties are needed in Eulychnia Philippi (1860: 23), Leucostele Backeberg (1953: 36) and Maihueniopsis Spegazzini (1925: 86) (Cactaceae Juss.).

The genus Trichocereus is represented by 19 taxa (12 species, 5 subspecies and 2 varieties) in Chile, 13 of them endemic to this country. These occur from the regions of Arica and Parinacota on the border with Peru, to the region of Maule, the IV Region of Coquimbo presenting the highest taxonomic richness. Its species are a dominant feature of the landscape and define phytogeographic regions. This taxonomic study has yielded iconographies, original descriptions, detailed descriptions, taxonomic comments, information on distribution and habitat, exsiccata, nomenclature, and three keys for the identification of species, subspecies and varieties. This treatment provides an updated synonymy including eight new synonyms; a new combination, Eulychnia coquimbana (Molina) S. Albesiano; three taxonomic level changes: (1) Trichocereus chiloensis subsp. australis (F. Ritter) S. Albesiano, (2) Trichocereus chiloensis subsp. eburneus (Phil. ex K. Schum.) S. Albesiano, and (3) Trichocereus chiloensis subsp. ...

The genus Eulychnia Philippi contains a small number of arborescent or shrubby cacti. Ritter (1980/81) accepted 9 species and a further 5 varieties although more recent authors, Hoffmann & Walter (2004) and Hunt (2006) have accepted a more conservative 4 species. With one notable exception, the genus is Chilean and is found over a range of 1500km from S18°40′ to S32°20′. The one exception is Eulychnia ritteri which grows in southern Peru at a single, disjunct locality, approximately 500 km north of the Chilean border (and nearest other Eulychnia populations), near the coastal town of Chala. The northern part of the Chilean range corresponds to the extremely arid Atacama Desert where Eulychnia is restricted to coastal localities. Rain is very infrequent and the plants survive on the coastal fogs, known locally as ‘camanchaca’. At the southern end of the range, regular winter rain fall allows the plants to grow away from the coast and into the low foothills of the Andes. Eulychnia is a poorly studied genus both in habitat and in cultivation. This is somewhat surprising on account of their very visible presence within many cactus habitats where large stands of the plants can dominate hillsides. However cactus explorers, with the exception of Ritter, have paid them scant attention. In cultivation they are occasionally found as small seed raised plants. They have a reputation of slow growth and rarely reach a size where flowers can be expected. The authors have made several trips to Eulychnia habitats and observed all the species in habitat. It became apparent that two populations did not fit comfortably within the four species concept as defined by Hunt. Both populations were described by Ritter as varieties and we believe they are better accepted as good species and we make the two new combinations required here.

Summary Coastal fog deserts along the coast of Northern Chile provide unusual opportunities to study mechanisms controlling structure and diversity of desert plant communities. At Paposo, Antofagasta Province, regular coastal fogs known as the Camanchaca hang against the steep coastal topography in a zone between 280 and 830 m. Despite a mean annual precipitation of less than 25 mm, fog drip provides sufficient moisture for the development of a luxuriant fertile zone. Below the fog zone vegetation is sparse, while above it vascular plant life is virtually absent. In the central fog zone vegetation coverage may reach 50 %. Individual growth forms of vascular plants sort out well along an elevational gradient through the fog zone. Woody deciduous species reach their greatest coverage within the central fog zone, while deciduous subshrubs reach maximum coverage at the margins of the fog zone. Succulents likewise have maximum coverages above and below the fog zone. Data on competitive relationships between Euphorbia lactiflua, a woody deciduous shrub, and Eulychnia iquiquensis, an arborescent cactus, indicate that high densities of Euphorbia in the central zone have little impact on densities of Eulychnia, but do reduce coverage values of this latter species. Species diversity of communities along an elevational gradient are not related to coverage values but are directly related to grow-form diversity, thus indicating intergrowth-form competition is greater than intra. growth-form.