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Background and aims – The Orchidaceae family is vulnerable, because of the destruction of their habitat, as well as the extraction of individuals from natural populations. This is the case of the genus Rhynchostele Rchb.f.; among the actions considered important for appropriate conservation strategies for this genus is the generation of fundamental knowledge, such as on its reproductive biology. The objective of this work is to understand the mating system and reproductive success of Rhynchostele cervantesii, an endangered epiphytic orchid endemic to Mexico.Material and methods – Manual and open-pollination treatments were conducted during 2014 and 2015 in a cloud forest in Michoacan, Mexico. In each period, 30 to 40 randomly selected inflorescences were subjected to the following treatments: a) spontaneous-self-pollination, b) emasculation, c) self-pollination, d) cross-pollination, and e) open-pollination. The developed fruits were counted and harvested, the viability of the seeds was determined, through the observation and evaluation of embryos using microscopy.Key results – Significant differences were recorded between the treatments in both 2014 and 2015, with higher fruit production in cross-pollination than in self-pollination and natural-pollination. There were significant differences in seed viability, with higher values for seeds from open-pollination and cross-pollination and lower values for seeds from self-pollination.Conclusions – Rhynchostele cervantesii is a species that requires pollinators for sexual reproduction because there is no fruit production with spontaneous-self-pollination. Under pollen limitation, the fruit set of natural pollination was a lot lower than in cross-pollination although fruits were the same quality. R. cervantesii had a mixed mating system with a tendency to exogamy, presenting high values of female reproductive success compared to other tropical epiphytic orchid species reported in the literature.

The first record of Telipogon helleri (Orchidaceae) in Mexico was in 2009. The relevance of this study is the finding and characterization of a second population of this taxon, in a new location, and the revaluation of the original population five years later of its discovery. In addition, we evaluated the new population by the Method of Evaluation of Risk of Extinction for plants in Mexico (MER-Plantas). We evaluated this species using the Risk Assessment Method of Extinction for plants in Mexico (MER- Plantas). The original population increased 1.7 % (15.38 % immatures; 84.62 % adults; n = 78 individuals), and was distributed among six phorophytes (four more than in 2009), with 73.08% of the individuals growing on twigs and with a similar number of individuals facing the different cardinal points. The new population was found in a cloud forest fragment, growing on a single phorophyte (Brunellia mexicana), consisting of 36 individuals (38.89 % immatures; 6.11 % adults), all of which were growing on the trunk and 69.44 % facing west. We suggest that T. helleri should be placed in the category of endangered (P), in the Mexican Oficial Standard for threatened ora and fauna. It is necessary to carry out demographic and molecular studies to evaluate the levels of endogamy and the genetic viability of the individuals present and to estimate the capacity for adaptation and population growth. The increase in the number of individuals in the last five years could be rapidly reversed given the adverse conditions prevailing in the habitats and localities where the two populations are found.

In vitro propagation could be an alternative for the conservation of the endemic and endangered Mexican epiphytic orchid Laelia speciosa (H.B.K.) Schltr. The goal of this study was to develop a protocol that would enhance acclimatization of in vitro – derived L. speciosa plantlets – a critical stage in propagation and subsequent conservation. Observations of stomata opening during ex vitro acclimatization, and the time of in vitro culture (0, 5, 10, 15, 20, 25, 30 days) in greenhouse conditions (pre-acclimatization), on the survival and development of seedlings during the ex vitro acclimatization were carried out. In addition, the effect of different levels of nutrients (100%, 75%, 50%, 25% and 0%-strength salts) and sucrose (0, 10, 20, 30, 40 g l−1) in the Murashige and Skoog medium (MS) on the same parameters were measured. Plantlets incubated 20 days in greenhouse conditions before ex vitro acclimatization also displayed the best growth with a survival rate of 97.5%, related with high stomata opening. Plantlets on MS containing 100%-strength salts (with 20 days of pre-acclimatization, 40 g l−1 sucrose) had the highest rate (97.5–100%) of survival and vigor when acclimatized. By improving micropropagation through acclimatization, the sustainable management of L. speciosa now more likely, benefitting the conservation of this endangered species.

Fungi-orchid relationships have been studied mainly in terrestrial orchids. The present work deals with diversity and biological role of the fungi associated to the epiphytic orchid Laelia speciosa through molecular evidence. ITS sequences confi rmed fungal presence in roots, capsules, seeds and in vitro seedlings. None of the fungi found formed characteristic pelotons, so we do not assume they are mycorrhizal. We identifi ed 18 taxa of fungi belonging to eight known genera (Alternaria, Curvularia, Cylindrocarpon, Fusarium, Myrmecridium, Neonectria, Penicillium, and Tetracladium) and unknown species of Atractiellales, Helotiales, Hypocreales, Lasiosphaeriaceae, Nectriaceae, Sordariomycetes, and Tricholomataceae. From these, we infer the biology of nine parasites, four saprobes, and two endophytes. One of the fungi, a Helotiales species, was able to colonize all orchid tissues, including seeds and in vitro seedlings, so, even if all precautions were taken, “axenic culture” of L. speciosa is a diffi cult task. There is a considerable diversity of fungi within L. speciosa organs. Endophytic fungi interact with the whole plant of L. speciosa along its life cycle.