The type of SI operating within the genus was considered to be best explained by gametophytic self-incompatibility (GSI) with interspecific variation in its phenotypic expression. The implications of these findings are discussed in relation to SI in the Pleurothallidinae and conservation strategies for Restrepia and related genera.

Restrepia is a small Pleurothallid genus, comprising 57 species, 44 of which were discovered since 1970. These species are indigenous to Central and South America, where their montane forest habitats are under increasing pressure from changes in land use. With resulting increasingly fragmented habitats and dwindling numbers, the pollination systems of obligate out-breeding genera, such as Restrepia, may no longer function efficiently which could potentially lead to their extinction. As such, the main aim of the current study was to perform an in-depth investigation of floral structures in the genus, using SEM and photographic technology to formulate a putative pollination mechanism for these species. The floral micromorphology of dorsal sepal and lateral petal osmophores, synsepal, labellum, cirrhi and calli were investigated by scanning electron microscopy (SEM), macro-photography and statistical analyses of some floral proportions. The secretory nature of the labellum, synsepal and osmophore papillae were established and the calli were shown to possess a unique papillate, non-secretory structure. A pollination mechanism for the genus was proposed which includes the role of the scent trails produced by the osmophores and the 'trapping' role of the cirrhi. A 'functional fit' between the flower and the pollinator is suggested. In conclusion, we consider Restrepia to represent a non-nectar rewarding and 'deceptive' orchid genus and that this pollination mechanism may be directly linked to the breeding system (gametophytic self-incompatibility) in this genus. Thank you for your favourable reply regarding our manuscript. Since which time, we have been addressing the minor revisions from your review. The main problem concerned entering species authorities into Table 1, about which I contacted you. We tried your suggestion to create a new table, but after due consideration found that this didn't work very well. Therefore, we decided to reformat Table I to include species authorities and have included the reference to the WCSP, (Kew) which is from where this information was obtained. Anyone wishing to check these data, should now be able to do so. All the minor text, spelling, formatting changes that you suggested were accepted via track changes. Our reponse to some of the other points you suggested for amendment are highlighted below in red. Pg 11 Line 207 eventually after consideration we decided on the following wordingWe consider them to be…… This expressed our hypothesis better, and still implied it was our idea and not proven fact Pg 12 lines 212-213 As this sentence was unclear, it has been omitted. The previous few lines, really had said everything that was required. Pg 12 lines 224-255 Comment 'thus, pollination may no longer occur during thus stage? and animals entering at this stage may not be pollinators?'The sentence has been rephrased. This seems to be an adaptation to bring about pollination if it has not occurred when senescence begins. The wording should now make this clearer. Pg 12 lines 226...

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Introduction35 Restrepia is a small orchid genus comprising 61 species (WCSP 2018) belonging to the 36 Pleurothallidinae, the largest sub-tribe in the Orchidaceae. These species are found throughout 37 Central America and in Venezuela, Colombia, Ecuador, Peru and Bolivia in South America, 38 growing at elevations between 1000 -3000 m a.s.l. in areas of montane rain forest. These forests 39 were identified as deforestation 'hotspots' by Mittermeier et al. (1999). Habitat loss and orchid 40 population decline in these regions has been ongoing (Mittermeier et al. 1999; Myers et al. 2000; 41 Brooks et al. 2002;Bubb et al. 2004;Millner 2013) and from this, it is reasonable to assume that 42 all epiphytic species, including Restrepia, face significant threats to their populations. However, 43 to date, the majority of Restrepia species have not been evaluated against Red List Criteria to 44 determine their degree of threat. Therefore, this study was designed to use information and data 45 currently available online to determine the degree of threat facing this genus and to establish their 46 Red List status, for later inclusion in the IUCN online data base.47 Figure 1 near here 48 The only comprehensive review of the genus is the monograph by Luer (1996a), which does not 49 include the most recently described species. The type species for the genus, Restrepia antennifera 50 (Humboldt et al. 1816) was described in 1801 (Figure 1). Together with other early discoveries, 51 such as R. contorta, R. brachypus and R. guttulata it is widely distributed geographically and 52 exhibits a high degree of within-species variation. The majority of Restrepia species have been 53 identified after 1980 and many of which have only been identified from one or two locations 54 (Luer 1996a). While these may persist in other localities in the wild, they have a narrower 55 geographical distribution compared to those discovered earlier. Species discovered since 1996