Red List Status -Endangered (EN) , assessed in 28/11/2018
The most significant morphological difference between H. minimum and H. pumilio is that the outer surfaces of the indusial flaps bear spines in H. minimum but not in H. pumilio. However, both species bear teeth on the margins of the indusial flaps. Of the other characters stressed in the protologue as differentiating H. pumilio,
there seems little difference in the rachis wing (absent, at least proximally, in both species), but the pinnae of H. pumilio do appear to be adjacent or more frequently imbricate, rather than not overlapping in H. minimum, and are generally more numerous. There are other differences not emphasised in the protologue, particularly
that H. pumilio is generally smaller and lacks the secondary segments found in H. minimum.
Hymenophyllum pumilio went undetected for just over 100 years between its initial collection and its rediscovery. Although H. pumilio is currently poorly known, it may not be as uncommon as the paucity of collections suggests.
LR Perrie, LD Shepherd, PJ Brownsey, J Larraín, B Shaw, L Thouvenot & M von Konrat (2016) Rediscovery and reinstatement of the New Caledonian endemic filmy fern Hymenophyllum pumilio Rosenst., New Zealand Journal of Botany, 54:1, 1-10, DOI: 10.1080/0028825X.2015.1100640
Hymenophyllum pumilio is a very small epiphytic fern on mossy tree's trunck endemic of New Caledonia. It is restricted to the north east of Grande Terre. This species was described in 1911 from a single collection from New Caledonia. It was not recorded again until its rediscovery during an expedition to New Caledonia in 2012. It grows on dense humid forest on mossy truncks at an altitude range of 200 and 700 m asl. Its population size in unknown but field observations indicate an uncommon species. Its area of occupancy (AOO) and extent of occurrence (EOO) respectively equal to 20 and 294 km² with four locations. Therefore, considering the potential impact of destruction of habitats by feral pigs (Sus scrofa) and bushfires at Tao and the small population size, H. pumilio is considered Endangered (EN) B1ab(iii,v)+2ab(iii,v).
Hymenophyllum pumilio is endemic to New Caledonia where it is only known from four localities restricted to the north east of Grande Terre.
Population size is unknown. However based on field's prospections it is an uncommon species.
Hymenophyllum pumilio is an epiphytic fern on mossy tree's truncks which occurs in dense humid forest from 200 to 700 m asl.
The main potential threats identified are invasive species such as feral pigs (Sus scrofa)) and bushfires at Tao which contribute to the decline of habitat quality.
Hymenophyllum pumilio is not protected by legislation in New Caledonia but it is present in one protected area: Mont Panié. This species is not sufficiently collected because of its small size. Propections is needed for herbarium specimens.
Del Rio, A. & al. 2017. Origins of the fern genus Hymenophyllum (Hymenophyllaceae) in New Caledonia: Multiple independent colonizations from surrounding territories and limited in situ diversification. Taxon(66(5)) , p.1041-1064.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Ebihara A.,Iwatsuki K., Ito M., Hennequin S., Dubuisson J.Y. 2007. A global molecular phylogeny of the fern genus Trichomanes (Hymenophyllaceae) with special reference to stem anatomy. Botanical Journal of the Linnean Society,(155(1)) , p.1-27.
Perrie L.R., Shepherd l;d;, Brownsey P.J., Larrain J., Thouvenot L., vn Konrat M. 2016. Rediscovery and reinstatement of the New Caledonian endemic filmy fern Hymenophyllum pumilio Rosenst.. New Zealand Journal of Botany,(54) , p.1-10.
Ebihara A., Dubuisson J.-Y., Iwatsuki K., Hennequin S., Ito M. 2006. A taxonomic revision of Hymenophyllaceae. Blumea(51(2)) , p.221-280.
Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Rouhan G., Bruy, D., Veillon J.-M., & M. Chalopin. 2019. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia..
Assessor(s): Amice, R., Butin, J., Garnier, D., Veillon, J., Fleurot, D., Laudereau, C., Suprin, B., Mandaoué, L.
Reviewer(s): Tanguy, V.
Contributor(s): Perrie, L., Rouhan, G.
Facilitator(s): Meyer, S., Warimavute, G.