Cynometra cebuensis Seidenschwarz, 2013

Cynometra cebuensis Seidenschwarz View in CoL , sp. nov. — Fig. 1 View Fig

Cynometrae copelandii (Elmer) Elmer proxima, habitatione in sylvis siccis calcareis (versus locis planis fertilibus sylvaticis secus flumines), foliis folio- lisque multo maioribus (his 4–6 cm versus 1.8–2 cm longis), inflorescentiae rhachide 14–16 mm longis (versus 2.5–4.5 mm), antheribus basi non fissis sine stamine sterili, ovario dense strigoso (versus laxe et longe pubes- centi) differt. — Typus: Seidenschwarz s.n. (holo L0820723 ; iso L0820722 , L0820721 ), Tabunan forest , Cebu.

Treelet up to about 12 m tall; no buttresses. Leaves (3–)4–6-ju- gate; petioles rugose, 5–7 mm, rachis 7.5–10 cm, both hairy, leaflets dark green, sessile, ovate to oblong, 2–5(–6) by 0.8–1.5(–2.2) cm, apex deeply emarginate; base asymmetric, acroscopic side cuneate, basiscopic side rounded to auriculate;

1 Cebu Biodiversity Garden, Paseo Annette 1, Maria Luisa Park, Banilad, Cebu City 6000, Philippines; e-mail: cebu@hk-diplo.de .

midrib 5–7 mm from the acroscopic margin; nerves 7–9 pairs, margin thickened. Inflorescence rachis 14–16 mm, laxly hairy; pedicels 8–10 mm, laxly hairy. Hypanthium 1 mm deep, short hairy outside. Sepals 5–7 mm long. Petals plain white 4–8 by 2–4 mm. Stamens 10 sometimes 9, 11 or 12, sterile one absent, filaments 6–8 mm long, anthers dorsifix, not cleft at the base. Ovary 3–5 by 1.5 mm, densely strigose; stipe 1 mm; style 3–5 mm, curved, hairy in the lower 1/3, upper part glabrous, stigma 0.4 mm. Fruit a woody pod, broadly obovoid to suborbicular, compressed, indehiscent, 4 by 2.6 cm, 2 cm thick, pedicel 12 mm long. Seed 2.2 by 1.8 cm, 1.1 cm thick.

Distribution — Philippines. Only known from Cebu island, (Tabunan forest in Central Cebu).

Habitat & Ecology — In dry forests on limestone, altitude 400– 600 m. Flowering occurs in March and early April, at the onset of the dry season. The flowers last only for a few days. Anthesis is three to five days. The fruits develop within 3 months and fall from the trees in July.

Notes — The species is most similar to Cynometra copelandii (Elmer) Elmer from Sibuyan island ( Elmer 1910, 1915, Hou et al. 1996). Both species possess 4–6 jugate leaves and emarginate leaflets. However, the new species differs significantly in a number of characteristics. The leaves and leaflets are much larger, 4–6 cm vs 1.8–2 cm in C. copelandii . It also differs in several floral characteristics. The flowers are purely white, instead of creamy white. The rachis of the inflo- rescence is 14–16 mm long in the new species vs 2.5–4.5 mm in C. copelandii . The anthers are not cleft at the base. Elmer (1910) reports that in C. copelandii , there is one sterile stamen, which is an exception in Cynometra . The new species has no sterile stamen. The ovary is densely strigose hairy whereas it is laxly long-hairy in C. copelandii .

The habitat of the new species differs as well. It grows in dry forests on limestone without any flowing water, whereas C. copelandii is recorded as growing in “moist fertile wooded flats” along the river.

Knaap-Van Meeuwen (1970: 13) states that all Indo-Pacific species of Cynometra grow under everwet climatic conditions, but Cebu has a distinct dry season of about 3 months from the middle of March to early June.

Growth rate & Morphology — A study was conducted on 17 trees, raised as seedlings from the seeds of one mother tree in the Tabunan forest and planted in 1999. The first tree flowered in March 2008, i.e. nine years after planting. The new species is a slow growing tree. Average height after 10 years is only 8 meters, and the average stem diameter 8.6 cm.

New tassels are formed several times a year – mostly as single branches only. The tassels of seedlings and young trees are bright pink, in older trees, they are bright creamy greenish yellow.

The newly opened tassels are visited by a number of insects. Observed were several species of Hymenoptera and Lepidop- tera (in particular Ariadne merione luzonia ).

Conservation status — Due to its restricted extent of occurrence and deteriorating habitat conditions, the new species can be classified as Critically Endangered (CR) according to the IUCN Red List Categories ( IUCN 2001). The species meets the criteria B1a and B1b (as well as B2a and B2b) for Critically Endangered.

The author is monitoring the forest since 1994. The Tabunan forest covers an area of approximately 1.45 km ² and its cir- cumference line amounts to 21 km. The forest is surrounded by agricultural land. Habitat deterioration is caused by timber harvesting and fires during the dry season. The nearby Canti- pla forest, a previous habitat of the new species, has virtually vanished. It is hoped that people will adopt the species and plant it in settlements because of its ornamental properties.