Podocarpus humbertii

de Laub. (1971)

Common names

None are known. The scientific name would transliterate as "Humbert's podocarp".

Taxonomic notes

Type: Madagascar, Antsiranana Prov., Anjanaharibe Massif, Mont Anjanaharibe, slopes and N summit, H. Humbert et al. 2474 (holotype P00559091). No synonyms.

There are, in this treatment, 5 species of Podocarpus on Madagascar, all endemic. They all belong to subgenus Podocarpus, section Scytopodium (de Laubenfels 1985). Molecular studies to consider this group include those by Knopf et al. (2012) and Khan et al. (2023), which both considered 2 of the 5 species (P. capuronii and P. madagascariensis) and assigned them to a clade shared with all of the African species. Leaf cuticle micromorphology has also proven to be a useful source of taxonomic characters in Podocarpus, and the analysis by Stockey et al. (1998), considering all Madagascar taxa of Podocarpus, found them very similar, which suggests that P. humbertii shares a clade with those other taxa.

Description

Dioecious shrubs or trees to 15 m tall. Bark exfoliating in small flakes, brown weathering to gray. Twigs spreading to erect, slender, round. Foliage buds subglobose with imbricate, triangular, obtuse scales. Leaves not dimorphic; crowded at tips of twigs, spreading at <50° from shoot, petiolate, overlapping each other and downcurved; obovate to oblanceolate, 7-15 × 2-4 mm; margins flat or slightly revolute; coriaceous, dark green above and paler green below; upper midrib inconspicuous, discontinuous, or in a groove; lower midrib continuous and wider, but flattened; apex obtuse, rounded, or sometimes acuminate. Pollen cones axillary in 1's and 2's on 3-6 mm peduncles, 8-20 × 2.5-3 mm. Seed cones axillary, solitary on 2-3 mm peduncles, the receptacle at maturity 3-5 × 2.5-4 mm, coriaceous. Seed solitary, ovoid-globose, within epimatium 11-15 × 9-12 mm, with a small inconspicuous crest (Farjon 2010).

The species is distinct from all other Madagascar Podocarpus in its remarkably small leaves; in any other species that occasionally bears such small leaves, they will be only 1-2 mm wide (Farjon 2010).

Distribution and Ecology

Madagascar: Antsiranana Province, where it occurs at elevations of 1600-2410(-2800?) m in subhumid forest, dry lowland deciduous forest, and ericaceous thickets on gneiss and granite mountain summits (Farjon 2010).

Distribution data for all species native to Madagascar, based on identified specimens listed by GBIF (2023). Each point includes a link to more data and, in most cases, an image. Podocarpus humbertii shown in purple.

The IUCN reports that this species is in decline. It is facing a very high risk of extinction in the wild due to severe fragmentation of its distribution, coupled with continuing decline in number and size of surviving populations.

Remarkable Specimens

No data as of 2023.02.05.

Ethnobotany

No uses are reported, but like other small trees in the region, it is likely used for firewood on occasion (Farjon 2010).

Observations

See the map above and the cited iNaturalist observation.

Remarks

The epithet honors H. Humbert, who collected the type specimen in 1950.

Citations

de Laubenfels, David J. 1971. Deux nouveaux Podocarpus endemiques de Madagascar. Adansonia ser. 2, 11(4):714-715. Available: Biodiversity Heritage Library, accessed 2022.12.23.

de Laubenfels, David J. 1985. A taxonomic revision of the genus Podocarpus. Blumea 30:51-278.

Khan, Raees, Robert S. Hill, Jie Liu, and Ed Biffin. 2023. Diversity, distribution, systematics and conservation status of Podocarpaceae. Plants 12(5):1171. https://doi.org/10.3390/plants12051171.

Stockey, Ruth A., Brenda J. Frevel, and Philippe Woltz. 1998. Cuticle micromorphology of Podocarpus, subgenus Podocarpus, section Scytopodium (Podocarpaceae) of Madagascar and South Africa. International Journal of Plant Sciences 159(6):923-940.

See also

The species account at Threatened Conifers of the World (no photos).