Monday, July 26, 2021

[Botany • 2021] Vaccinium exiguum (Ericaceae: Vaccinieae) • A New Species from the Ultramafic Summit of Mt. Victoria, Palawan Island, Philippines


Vaccinium exiguum M.N.Tamayo, R.Bustam. & P.W.Fritsch

in Tamayo, Bustamante et Fritsch, 2021.

Abstract
Vaccinium exiguum from the ultramafic summit of Mt. Victoria, Palawan Island, Philippines is here described as a new species of Ericaceae. It closely resembles V. hamiguitanense but is distinct by having much shorter petioles and leaves, longer and glabrous calyx lobes with serrate lobe margins, a larger corolla with deeper sulcations, and longer stamens with spurs oriented laterally. Vaccinium exiguum represents the third Vaccinium species found on the Island of Palawan and 36th in the Philippines.

Keywords: Ericales, endemic species, Malesia, sect. Bracteata, Vaccinioideae


Figure 2.Vaccinium exiguum M.N.Tamayo, R.Bustam. & P.W.Fritsch 
 A flowering branchlet B leaf, abaxial view C lateral view of flower showing ribbed corolla D distal portion of pedicel, as well as hypanthium, calyx lobes and style E stamen in oblique-lateral view showing spurs F stamen in ventral view G cross section of ovary showing seven locules.
Illustrated by Maverick N. Tamayo.

Figure 1. Vaccinium exiguum M.N.Tamayo, R.Bustam. & P.W.Fritsch
A ultramafic summit of Mt. Victoria B flowering branchlets in situ.
Photo A by Alastair Robinson. Photo B by Rene Alfred Anton Bustamante.



Vaccinium exiguum M.N.Tamayo, R.Bustam. & P.W.Fritsch, sp. nov.
 
Diagnosis: Vaccinium exiguum closely resembles V. hamiguitanense, but is distinct by having shorter petioles (0.5–1.0 mm vs. 1.2–1.8 mm), shorter leaves (4.9–9.3 mm vs. 8.8–16.0 mm), longer calyx lobes (1.8–2.0 mm vs. 1.1–1.3 mm) that are glabrous (vs. merely ciliate) with serrate calyx lobe margins (vs. entire), a larger corolla (6.0–7.0 × 4.0–5.0 mm vs. 4.6–5.0 × ca. 2.6 mm) with deeper (vs. shallow) sulcations, and longer stamens (3.5–4.0 mm vs. 2.8–3.5 mm) with spurs oriented laterally (vs. slightly upcurved and oriented ± apically). The calyx lobes of V. exiguum are unique amongst Philippine species in that they are nearly as long as or longer than the hypanthium. Unlike V. hamiguitanense, V. exiguum has a corolla that appears distinctly star-shaped in cross section because of its deep sulcations.

Etymology: The epithet “exiguum” refers to the overall small stature and leaf morphology of the new species.

Distribution and habitat: Vaccinium exiguum is currently known from a single individual from a single location at the exposed ultramafic forest summit of Mt. Victoria, Palawan Island, Philippines at ca. 1700 m elevation.

     


 Maverick N. Tamayo, Rene Alfred Anton Bustamante and Peter W. Fritsch. 2021. Vaccinium exiguum (Ericaceae, Vaccinieae), A New Species from the Ultramafic Summit of Mt. Victoria, Palawan Island, Philippines. PhytoKeys. 179: 145-154. DOI:  10.3897/phytokeys.179.68323

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