Gastrodia selabintanensis Tsukaya & A.Hidayat, 2016

Tsukaya, Hirokazu & Hidayat, Arief, 2016, A new species of Gastrodia (Orchidaceae: Gastrodieae, Epidendroideae) from Java, Phytotaxa 273 (1), pp. 77-80 : 77-79

Gastrodia selabintanensis Tsukaya & A.Hidayat , sp. nov. (Fig. 1,2)

Type: — INDONESIA. Java: Selabintana , along a trail under montane forest, 6°50’40”S ; 106°57’54”E,. ca. 1,030 m, 10 March 2016, Hidayat AH5405 (holotype: BO!, a flower in spirit and a standard dried specimen; isotype: TI!, a flower in spirit and a standard dried specimen) .

Gastrodia selabintanensis differs from other members of Gastrodia sect. Codonanthus by having a long perianth tube (17 mm), a short, open mouth of the perianth tube (5 mm), a lip longer than the column (10–12 mm), and stelidia on the column that are slightly shorter than the anther cap.

Terrestrial, mycoheterotrophic, perennial herbs. Plant erect, inflorescences unbranched. Roots filiform, mostly extending from the rhizome apex. Rhizome tuberous, fusiform or cylindrical, 3–6 cm long, 0.5 cm in diameter, purplish brown, covered with hairs. Stem glabrous, purplish brown, 15–25 cm long, 0.2–0.3 cm diameter, ± 5 sterile nodes with membranous sheaths/ scale leaves of 5–7 mm long. Bracts triangle, acute, 7–9 mm long, purplish brown. Pedicels 10 mm long, ovary 6 mm long. Flowers 2–4, tubular, erect, respinate, 17 × 9 mm. Sepals and petals united, forming a five-lobed perianth tube. Sepals subsimilar, 17 mm long, connate ca. 3/4 of their length with petals, laterals connate ca. 3/4 with each other, outer surface slightly greenish brown, verucose with pale spots, margins slightly wavy; free part of dorsal sepal triangular, retuse; free part of lateral sepals triangular, acute at apex, 5 mm long. Free part of petals ovoid with acute apex, 4 × 4 mm, white-tinged with yellow at apices. Lip joined with the perianth tube at its base, 10–12 × 4 mm, hypochile white with two white calli; epichile white, rectangular with a narrow base and a rounded, yellow apex, disc 4-ridged, margin undulate. Column straight, semicylindrical, 7.5 mm long, white; stelidia distinct, triangular, acute, the edges parallel to the column. Anther rectangular, ca. 2 mm in diameter, pale yellow, pollinia 2. Fruits and seeds not seen.

Distribution and phenology: — The species is only known from the type locality, Java, Indonesia; flowering in March.

Etymology: — The new species is named after the type locality.

Note: — This species has a short inflorescence stem (<40 cm) at flowering, indicating that it belongs to section Codonanthus ( Schlechter 1911) . The most conspicuous feature of this new species is its 17 mm perianth tube, with a slender 15–25 cm inflorescence.Among members of section Codonanthus , only G. crispa Smith (1921: 248) , G. longitubularis Meng, Song & Luo (2008: 23) , G. fontinalis Lin (1987: 129) , G. takeshimensis Suetsugu (2013: 375) and G. flexistyloides Suetsugu (2014: 270) share the same characters. Among these five species, none shares the white, long lip character (11–12 mm long) with this new species. Morphologically, G. takeshimensis is most similar to G. selabintanensis . Gastrodia takeshimensis is a completely cleistogamous species ( Suetsugu 2013); G. selabintanensis opens its flower slightly, suggesting that G. selabintanensis displays an evolutionary intermediate between outcrossing and cleistogamy. Further analysis will reveal whether this is the case or not.

Key to the species of Gastrodia in Java (modified from Comber 1990).

1. Height 50 cm or more at flowering; corolla tube split open along lateral sepal margins almost to the base ( Gastrodia sect. Gastrodia ........................................................................................................................................................................... G. javanica

1. Height 40 cm or less; corolla tube split open along lateral sepal margins to no more than 3/4 of their length ................................. 2

2. Inflorescence 1- or 2-flowered only; stelidia on the column projecting well beyond the anther cap ................................. G. callosa

2. Inflorescence with more than 2 flowers; stelidia only as long as or shorter than the anther cap. ..................................................... 3

3. Flower length 10.0 mm or less; petals more or less spherical, 2 mm long ..................................................................... G. verrucosa

3. Flower length 13 mm or more; petals 3.5 mm or more long............................................................................................................. 4

4. Flowers ± 13 mm long; lip margins straight.................................................................................................................. G. abscondita

4. Flowers ± 16 mm long; lip margins wavy.......................................................................................................................................... 5

5. Lip 6–8 mm long, shorter than column ................................................................................................................................. G. crispa

5. Lip 10–12 mm long, longer than column .............................................................................................................. G. selabintanensis