A Change in Conservation Status of Pachyphytum caesium (Crassulaceae), a Threatened Species from Central Mexico Based on Genetic Studies.

Genetic studies in rare species are important to determine their patterns of genetic diversity among populations and implement conservation plans aimed to reduce extinction risks. Pachyphytum caesium is an endemic species with extremely small populations in central Mexico. This work analyzes the diversity and genetic structure of Pachyphytum cesium (Crassulaceae) to change the conservation status and propose conservation strategies. Twelve dominant ISSR markers were used to describe the genetic diversity of all known populations. Additionally, we carried out two simulations to explore how the loss of individuals or the local populations extinction affect the genetics parameters of the species. The average results indicated moderate levels of genetic diversity (number of alleles = 89.7 ± 3.9, expected heterozygosity = 0.212 ± 0.0, and percentage of polymorphic loci = 56.1 ± 3.9), parameters that decreased significantly when simulations were performed in P. caesium. Additionally, a genetic structure of the populations was found with low gene flow (Nm = 0.92). Genetic parameters are negatively affected by the loss of individuals and the local extinction of populations. Based on our results, we propose to reclassify the conservation status of the species in danger of extinction, hence a series of conservation strategies are provided to prevent its disappearance.

Chayamaritia vietnamensis (Gesneriaceae), a new species from Son La Province, northern Vietnam.

Chayamaritia vietnamensis, a new species from Son La Province, northern Vietnam, is described and illustrated. The phylogenetic study revealed that the new species is most closely related to C. banksiae and C. smitinandii. The morphological comparison suggests it as the third new species of Chayamaritia and distinguished from C. banksiae and C. smitinandii by a combination of morphological characters of leaf blades, bracts, calyx and corolla, especially its peltate leaf blades. This species is provisionally assessed as endangered (EN B1ab(iii), B2ab(iii)) using IUCN Categories and Criteria. Information on ecology, phenology and an identification key for the known Chayamaritia species are also provided.

Primulina papillosa (Gesneriaceae), a new species from limestone areas of Guangxi, China.

Primulina papillosa Z.B. Xin, W.C. Chou & F. Wen, a new species from limestone areas of Guangxi, China, is described and illustrated here. It morphologically resembles P. linearifolia (W.T. Wang) Yin Z. Wang and P. pseudolinearifolia W.B. Xu & K.F. Chung, but can be easily distinguished by some combined characters, especially its leaf blades densely papillose-hispid. We found only one population at the type locality with no more than 200 individuals, so that this new species is provisionally assessed as Critically Endangered (CR) using IUCN Criteria.

Primulina hochiensis var. ochroleuca (Gesneriaceae), a new variety from a limestone area of Guangxi, China, and errata on five new species of Primulina.

Primulina hochiensis var. ochroleuca, a new variety from a limestone hill of karst areas, Guangxi, China is described with color photographs. It resembles P. hochiensis var. hochiensis, P. hochiensis var. ovata and P. hochiensis var. rosulata, but can be easily distinguished by a combination of characteristics, especially by its corolla color. We found only one population with approx. 3000 mature individuals at the type locality. This variety is provisionally assessed as vulnerable [VU C1] using IUCN criteria.

Primulina flexusa sp. nov. (Gesneriaceae) from Guizhou Province, China.

The limestone regions of Yunnan-Guangxi-Guizhou in southern and southwestern China are regarded as some of biodiversity's hotspots for China's Gesneriaceae where numerous rare new species of Primulina have been, or are being, described over the past two decades. Primulina flexusa, a new lithophytic species of Gesneriaceae from a limestone hill in a Karst area, from Guizhou, China, is described here with color photographs. It is similar to P. curvituba, but can be easily distinguished by a combination of characteristics, especially in the shape and length of its capsule. We found only one population with approximately 100 mature individuals at the type locality. This new species is provisionally assessed as Critically Endangered [CR C1] by using IUCN criteria.

Michaelmoelleria (Gesneriaceae), a new lithophilous dwelling genus and species with zigzag corolla tube from southern Vietnam.

Michaelmoelleria, a new genus from southern Vietnam is described with a single species, M. vietnamensis. The new genus is morphologically most similar to Deinostigma and Tribounia but it differs from the latter two by having four fertile stamens. Nuclear ribosomal internal transcribed spacer (ITS) region and plastid trnL-F intron spacer (trnL-F) DNA sequence data from the new genus and eighty-seven species representing 42 genera within tribe Didymocarpeae are used to resolve its generic placement. The molecular evidence reveals that it is most closely related to Cathayanthe rather than Deinostigma and Tribounia. The chromosome number is counted as 2n = 36 that further clarified its distinction comparing to the related genera within tribe Didymocarpeae. A global conservation assessment is also performed and classifies Michaelmoelleria vietnamensis as Critically Endangered (CR).

Kindia (Pavetteae, Rubiaceae), a new cliff-dwelling genus with chemically profiled colleter exudate from Mt Gangan, Republic of Guinea.

A new genus Kindia (Pavetteae, Rubiaceae) is described with a single species, Kindia gangan, based on collections made in 2016 during botanical exploration of Mt Gangan, Kindia, Republic of Guinea in West Africa. The Mt Gangan area is known for its many endemic species including the only native non-neotropical Bromeliaceae Pitcairnia feliciana. Kindia is the fourth endemic vascular plant genus to be described from Guinea. Based on chloroplast sequence data, the genus is part of Clade II of tribe Pavetteae. In this clade, it is sister to Leptactina sensu lato (including Coleactina and Dictyandra). K. gangan is distinguished from Leptactina s.l. by the combination of the following characters: its epilithic habit; several-flowered axillary inflorescences; distinct calyx tube as long as the lobes; a infundibular-campanulate corolla tube with narrow proximal section widening abruptly to the broad distal section; presence of a dense hair band near base of the corolla tube; anthers and style deeply included, reaching about mid-height of the corolla tube; anthers lacking connective appendages and with sub-basal insertion; pollen type 1; pollen presenter (style head) winged and glabrous (smooth and usually hairy in Leptactina); orange colleters producing a vivid red exudate, which encircle the hypanthium, and occur inside the calyx and stipules. Kindia is a subshrub that appears restricted to bare, vertical rock faces of sandstone. Fruit dispersal and pollination by bats is postulated. Here, it is assessed as Endangered EN D1 using the 2012 IUCN standard. High resolution LC-MS/MS analysis revealed over 40 triterpenoid compounds in the colleter exudate, including those assigned to the cycloartane class. Triterpenoids are of interest for their diverse chemical structures, varied biological activities, and potential therapeutic value.

Habitat specificity of a threatened and endemic, cliff-dwelling halophyte.

Coastal areas and other saline environments are major contributors to regional and global biodiversity patterns. In these environments, rapidly changing gradients require highly specialized plants like halophytes. In European coastal cliff-tops, rocky and sandy seashores, and saltmarshes, typical halophytes from the genus Limonium are commonly found. Among them, the aneuploid tetraploid (2n = 4x = 35, 36, 37) Limonium multiflorum, endemic to the west coast of Portugal, is an interesting case study for investigating the ecology and conservation of a halophyte agamospermic species. Although it is listed in the IUCN red list of threatened species, information on its population size or rarity, as well as its ecology, in some respects is still unknown. Field surveys in the largest known population were performed (Raso cape, Portugal) in order to determine habitat requirements and conservation status. A total of 88 quadrats were monitored, 43 of which contained at least one L. multiflorum individual. For each sampled quadrat, four abiotic and four biotic variables as well as two spatially derived variables were recorded. Principal component analysis and cluster analysis showed narrow habitat specificity for this species which appeared to be intolerant to competition with invasive alien plants. We conclude that in situ conservation in a local 'hotspot' of this rare and vulnerable species emerges as a priority in order to ensure that biodiversity is not lost.