Foliage on a tree in habitat. iNaturalist observation 120027514 [James Ojascastro, 2022.06].
One photograph of a living plant is available at Threatened Conifers of the World, and Mill (2015) provides excellent line drawings.
Foliage on a tree in habitat. iNaturalist observation 120027514 [James Ojascastro, 2022.06].
One photograph of a living plant is available at Threatened Conifers of the World, and Mill (2015) provides excellent line drawings.
Podocarpus urbanii
Yacca, Blue Mountain yacca, mountain yacca (Mill 2015 and sources therein).
Lectotype: Jamaica, Saint Andrew Parish, near Cinchona, 1899.12.09, “a tree 20 feet high, 5000 feet altitude”, W. Harris 7798 (B; isolecto NY) (Mill 2015, where typified). Nearly all authors since the early 20th century have recognized this as a distinct and distinctive species. Syn. Podocarpus coriaceus sensu Hooker 1842, Endlicher 1847, Grisebach 1862, Parlatore 1868, Fawcett 1891, Orr 1944, all p.p., non Richard 1826; P. jamaicensis Nelson 1866 p.p.
See Podocarpus_angustifolius for notes on phylogenetic relationships between the Caribbean species of Podocarpus.
Trees 5-12(-25) m tall and 150 cm dbh with spreading branches forming a wide crown in mature trees. Bark smooth, dark reddish brown. Twigs diverging at 50–60°, 80–170 long, 1.8–2.5 mm thick, straight or slightly curved, greenish in first year turning gray-brown by third year. Buds globose, 2-4 mm diameter, composed of 12-16 overlapping keeled scales, 1-1.5 × 0.7-1.2 mm, apex obtuse. Leaves slowly deciduous, persisting 1-2(-3) years; juvenile and shade leaves larger than adult sun foliage. Flushing leaves yellow, maturing glossy gray-green above, matte gray-green below. Leaves densely crowded, spirally arranged, diverging at 30-65°, with a 1-2 mm petiole, narrowly oblong-elliptic, straight or slightly falcate, size varying from 30-60 × 5-9 mm (juvenile and shade foliage) to 20-30 × 3-5 mm (sun foliage), coriaceous, somewhat stiff, margin revolute; upper midrib proximally raised, fading distally; lower midrib distally grooved, bordered by narrow striate bands, proximally flat to somewhat raised; apex acute and aristate, base short-attenuate. Pollen cones axillary, solitary, sessile, cylindrical, 12-15 × 4 mm. Pollen white. Seed cones axillary on peduncles <1 mm long, receptacles swelling to 7-8 × 6 mm, red, succulent; epimatium stomatiferous, not swollen at maturity, shortly cleft at summit, olive green at all stages, nearly smooth or slightly wrinkled; seed symmetrical, ellipsoid, 4.4-7 × 3-4 mm, dark green turning blackish when ripe, crested. New leaves, ripe pollen cones, and receptive seed cones typically November-January, i.e. end of main wet season and into the dry season). Ripe seed cones mid- to late June, i.e. beginning of summer dry season (Farjon 2010, Mill 2015).
The narrow leaves (2–7 mm wide) and preference for acid soils distinguish Podocarpus urbanii from the only other Jamaican podocarp, P. purdieanus, which always occurs on limestone and has leaves 8–17 mm wide (Mill 2015).
Jamaica, confined to the Blue Mountains and John Crow Range only, at elevations of 1160-2256 m (the summit of Blue Mountain Peak, the highest point on Jamaica). Precipitation exceeds 2700 mm/yr, perhaps as much as 7500 mm/yr in parts of the John Crow Range. Soils are acidic/siliceous, with pH <5, derived from igneous, metamorphic, and sandstone rocks. Habitat is high montane, high-rainfall closed-canopy broadleaf forests, where this species is locally dominant, becoming one of the commonest trees at very high altitudes. It is the fourth most abundant tree in the Blue Mountains, on the basis of both stem density and basal area. In elfin woodland, Podocarpus urbanii forms part of a single woody stratum together with Clethra alexandri and Clusia havetioides; all bear a heavy epiphyte load of mosses and liverworts, with many small bromeliads, orchids, ferns and lichens. It is moderately shade tolerant and sprouts extensively on stems that become damaged, as after hurricanes. However, it seldom regenerates by seed. It maintains very high diameter growth rates, which may be an adaptation to survival in the hurricane-prone forests. For example, one long-term study of survival after 1988’s Hurricane Gilbert found that P. urbanii was the least susceptible to hurricane crown damage of the 48 studied species (Mill 2015 and sources cited therein).
Distribution data for all species native to the Caribbean, based on confirmed specimens cited by Mill (2015), using data from herbarium sheets. Data include both latitude/longitude and narrative location descriptions; coordinate uncertainty generally <5000 m. Podocarpus urbanii shown in red.
The rufous-throated solitaire, Myadestes genibarbis, nests in this species (Mill 2015 and sources cited therein).
The IUCN assesses this species as "Critically Endangered" due to a very small extent of occurrence, 50 km2, representing a single population within the ridge forest of the Blue Mountain and John Crow Mountains National Park. There are also thought to be a number of inaccessible stands that have not yet been documented. Despite being in a protected area, this habitat is still under considerable threat from deforestation resulting from subsistence and commercial farmers using slash and burn techniques to convert forests to agricultural land. Illegal timber harvesting is also a significant threat. Invasive tree species such as Pittosporum undulatum are rapidly spreading in closed canopy forests and along tracks and streams; these also represent a threat (Campbell and Meikle 2013, Bellingham et al. 2005).
No data as of 2023.01.07.
Formerly, this was a prized timber tree, much used in furniture and cabinet work. Indigenous farmers have recently held it as very good for timber and fuel, and reasonable for fence posts, tool handles and sticks (Mill 2015 and sources cited therein).
There is a trail to the summit of Blue Mountain Peak, where this species is said to be abundant.
The epithet honors German botanist Ignatz Urban (1848-1931), authority on Caribbean botany.
Bellingham, P. J., E. V. J. Tanner, and J. R. Healey. 2005. Hurricane disturbance accelerates invasion by the alien tree Pittosporum undulatum in Jamaican montane rain forests. Journal of Vegetation Science 16:675–684.
Campbell, K. and J. Meikle. 2013. Podocarpus urbanii. The IUCN Red List of Threatened Species 2013: e.T34106A2845925. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34106A2845925.en, accessed 2023.01.17.
Mill, R. R. 2015. A monographic revision of the genus Podocarpus (Podocarpaceae): II. The species of the Caribbean bioregion. Edinburgh Journal of Botany 72(1):61-185. https://doi.org/10.1017/S0960428614000328.
Pilger, Robert Knud Friedrich. 1903. Taxaceae. V. 18[IV,5] p. 89 in H.G.A. Engler, ed., 1900 - 1953. Berlin: Das Das Pflanzenreich. Regni vegetabilis conspectus. Available: Real Jardin Botanico, accessed 2023.01.17.
The species account at Threatened Conifers of the World.
Bellingham, P. J., E. V. J. Tanner, and J. R. Healey. 1994. Sprouting of trees in Jamaican montane forests, after a hurricane. Journal of Ecology 82:747–758.
Dasgupta, B., B. A. Burke, and K. L. Stuart. 1981. Biflavonoids, norditerpenes and a nortriterpene from Podocarpus urbanii. Phytochemistry 20(1):153–156.
Last Modified 2023-02-26
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