The Gymnosperm Database

Several photographs of living plants are available at Threatened Conifers of the World, and Mill (2015) provides excellent line drawings.

 

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Conservation status 2013

Podocarpus purdieanus

Hook. 1844

Common names

Yacca (Campbell and Gardner 2013), St. Ann's yacca (Mill 2015).

Taxonomic notes

Type: Jamaica: “Woods on mountain ridges, on the estate of Dunrobin Castle, the property of J. Tasker, Esq. St. Mary in the East, Jamaica; at an elevation of about 2,500 to 3,500 feet above the level of the sea”, William Purdie s.n. (holo K).

Syn: Nageia purdieana (Hook.) F.Muell. 1876; N. purdieana (Hook.) Kuntze 1891, comb. illegit.; Podocarpus jamaicensis Nelson 1866 p.p. Certain errors in nomenclature by Carrière, perpetuated in several editions of his Traité des Conifères, have resulted in the name P. purdieanus being applied to several South American podocarps. The species is a Jamaica endemic (Mill 2015).

See Podocarpus_angustifolius for notes on phylogenetic relationships between the Caribbean species of Podocarpus.

Description

Dioecious tree 10-40 m tall and up to 100 cm dbh, typically with a single trunk and a rounded crown in mature trees. Bark thin, smooth, becoming scaly, brown weathering to gray. Twigs divergent at 50-70°, 70-260 × 2-4 mm, straight or slightly curved, green to greenish brown, yellowish gray by third year. Buds broad-ovoid, 3.5-6.5 × 2.6 mm; 9-12 scales, 2.5-3.5 × 1.3-1.5 mm, all overlapping, ovate, greenish brown, not keeled, tips erect or spreading. Leaves persistent to base of young twigs, fairly crowded, spirally arranged, 7-20 mm apart, diverging from axis at 30-65°. Adult and juvenile leaves similar in shape, juvenile sometimes larger. Leaves yellow-green at flush, maturing glossy green above and pale matte green beneath. Leaves on mature trees petiolate, linear-lanceolate but wider above the middle, 36-105 × 10-16 mm (juveniles up to 170 mm long), straight or slightly falcate, coriaceous; both upper and lower midrib proximally raised and distally flat or grooved, with a broad striate band on each side of lower midrib; apex acute, aristate; base asymmetric, cuneate or short-attenuate. Pollen cones axillary, solitary, sessile, cylindrical, 14-23 × 2.7-6.5 mm, ripe at same time as leaf flushing. Pollen white. Seed cones lateral on a 1-4 mm peduncle, receptacle fleshy, slightly swollen when mature and then red to violet, not glaucous, composed of 1 sterile and 1 fertile bract, obovoid, 6.4-8.5 mm along longer edge, 4.8-6 mm long along shorter edge, 1.8-4 mm wide at top; scales connate, both with keeled free tips. Epimatium fleshy, not swollen, very shortly cleft at summit with smooth entire margin, olive-green when ripe, nearly smooth. Seed asymmetrically inserted on receptacle, obovoid, 5.5-7 × 3.4-5 mm, crested. Leaf flush and ripe pollen cones at end of primary wet season in November. Seed cones ripe at end of winter dry season in March/April (Farjon 2010, Mill 2015).

Both Podocarpus purdieanus and P. urbanii are native and endemic to Jamaica. P. purdieanus has leaves 10-16 mm wide while P. urbanii has leaves 2-7 mm wide. Also, P. purdieanus always grows on limestone but P. urbanii is always found on siliceous acid soils (Mill 2015).

Distribution and Ecology

Jamaica, mainly on Mt. Diablo and in ‘Cockpit Country’, a karst landscape in west-central Jamaica. There is one outlying collection, the holotype, from the east of the island in St. Thomas parish, Surrey county. The species has also been introduced to Martinique. Historically, there are scattered records across the island, suggesting that currently we see a remnant distribution following habitat loss due to logging and clearing land for agriculture. Podocarpus purdieanus occurs at (550-)730-1200 m elevation on carbonate soils, in wet seasonal forest and on mountain ridges. Typical canopy associates include Brosimum alicastrum, Buchenavia tetraphylla, Cecropia peltata, Cojoba arborea, Sideroxylon portoricense subsp. portoricensis, Manilkara excisa, Nectandra membranacea, N. sanguinea, Prunus occidentalis, Sloanea jamaicensis, Zanthoxylum martinicense and Ziziphus chloroxylon (Mill 2015 and sources cited therein). Based on data from 5 collection localities, P. purdieanus grows under a mean annual temperature of 22°C, with an average minimum in the coldest month of 17°C, and a mean annual precipitation of 1960 mm (Biffin et al. 2011, Table S5).

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 purdieanus shown in dark green.

The IUCN reports that this species is facing a very high risk of extinction in the wild due to severe fragmentation of its distribution, coupled with continuing decline in extent and quality of habitat and size of surviving populations. There is also some continuing exploitation, e.g. cutting for yam sticks (Ethnobotany). Although it occurs in some protected areas, enforcement and monitoring of illegal logging in protected areas is problematic, and the species' main area of distribution is threatened by bauxite mining (Campbell and Gardner 2013).

Remarkable Specimens

With regard to large trees, the only measurement I have seen is 107 cm dbh for a tree in habitat, with some trees to 36 tall (Hooker 1844). There are no data on old trees.

Ethnobotany

The wood has been said to be more valuable than mahogany for furniture making, and when common it was used for ship building, house construction, flooring, and furniture. More recently, sticks are cut from it for use in yam cultivation (Farjon 2010). There is also some pharmacological potential; Wang et al. (1997) isolated three new norditerpenoid dilactones from this species, which show cytotoxicity against cells causing human lung, breast and colon cancers.

Observations

No suitable locations are reported.

Remarks

The epithet honors William Purdie (ca. 1817-1857), who trained as a gardener at the Royal Botanic Garden Edinburgh. In 1843 he was sent to Jamaica by William Hooker and in 1846 he became superintendent of the Botanic Garden on Trinidad. He collected extensively in the Caribbean and Mesoamerica, especially in Jamaica, Colombia, Panama and Venezuela. He collected the type specimen of this tree, relating to Hooker that "this new kind reaches to 120 feet or more, and is really one of the noblest trees in the island. Its growth is rapid. One tree, felled by the proprietor, measured 3 feet 6 inches in diameter, at 6 feet from the ground, and at 39 feet from the ground, 2 feet 9 inches, without a branch up to that height. Many of the branches even afford good timber" (Purdie as quoted by Hooker [1844]).

Citations

Campbell, K. and Gardner, M. 2013. Podocarpus purdieanus. The IUCN Red List of Threatened Species 2013: e.T34094A2845186. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34094A2845186.en, accessed 2023.01.17.

Hooker, William Jackson. 1844. Icones plantarum 7: t. 624. Available: Biodiversity Heritage Library, 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.

Wang Xiping, Ping Cai, Ching-Jer Chang, David K. Ho, and John M. Cassady. 1997. Three new cytotoxic norditerpenoid dilactones from Podocarpus purdieanus Hook. Natural Product Letters 10(1):59-67.

See also

The species account at Threatened Conifers of the World.

Last Modified 2023-02-26