Apocynaceae

Takeuchi, Wayne, 2013, Floristic records from the upper Sepik of Papua New Guinea: Aristolochia chrismülleriana sp. nov. (Aristolochiaceae), Monanthocitrus paludosa (Rutaceae), and Secamone timorensis (Apocynaceae), Phytotaxa 114 (1), pp. 51-57 : 52

Apocynaceae

Secamone timorensis Decaisne (1844: 502) . Type:— INDONESIA. East Nusa Tenggara: Timor, Riedlé s.n. [P (photo BRI, fide Forster 1991)].

Additional specimen examined: — PAPUA NEW GUINEA. East Sepik Province: Ambunti District, Waskuk Hills, ridgeline north of Garuka , foothill forest, 4°11'05"S, 142°44'16"E, 120 m, 19 November 2004, Takeuchi, Towati & Ama 17278 ( A!, BO!, BRI!, E!, K!, L!, LAE!) .

The staminal corona lobes of Secamone timorensis are lanceolate (about as long as broad), but subulatecylindrical in S. elliptica Brown (1810: 464) , the only other species of Secamone s. l. known for Papuasia (cf. Forster 1996). The corolla lobes are also 2 – 3 × longer in S. timorensis (4.5–6 mm) than in S. elliptica (1.5–2 mm).

Secamone timorensis has been recorded from Timor, Irian Jaya, and Western Australia ( Forster 1991). Despite its apparently wide distribution, the species is represented by only a few fertile collections (ibid.). The single historical specimen from Irian Jaya was obtained from the Cycloop Mts. at Hollandia, near the border between Indonesia and PNG. With the recent gathering from Waskuk ( Fig. 2 ), the species is now documented across the border and into PNG, ca. 300 km to the southeast. Judging from taxa with similar cross-border distributions in New Guinea (viz. distributions conforming to the north-central accretionary phase; Pigram & Davies 1987) S. timorensis probably ranges further east into the Momase region and west to the Mamberamo River.

Figures

FIGURE 2. Secamone timorensis Decne. A, corolla limb in frontal view; B, flowering aspect, inflorescences branched through 2–4 orders; C, abaxial leaf surfaces. A–C from Takeuchi, Towati & Ama 17278.