Wednesday, September 7, 2016

[Botany • 2016] Gastrodia selabintanensis • A New Species of Gastrodia (Orchidaceae: Gastrodieae, Epidendroideae) from Java

Gastrodia selabintanensis  
Tsukaya & A.Hidayat 

Gastrodia Brown (1810: 330) is a mycoheterotrophic genus of Orchidaceae that consists of ca. 50 species (Tan et al. 2012, Suetsugu 2014, Huang et al. 2015). It is characterized by a fleshy tuber or coralloid root system, fused sepals and petals, and two mealy pollinia without caudicles. Since most Gastrodia species have completely fused sepals and petals, observation of the perianth is difficult, and identification of this genus is often imprecise. As a result of re-examination of floral characters, several new taxa in this genus have been reported in China, Taiwan, Japan, Madagascar and other countries during the last decade (Meng et al. 2007, Hsu et al. 2010, Hsu & Kuo 2011, Yeh et al. 2011, Hsu et al. 2012, Tan et al. 2012, Suetsugu 2013, 2014, Huang et al. 2015, Martos et al. 2015). Most of these new taxa belong to the section Codonanthus (Schlechter 1911), which has a short inflorescence (<40 cm).

In 2016, we visited Selabintana, West Java, Indonesia, and conducted a preliminary survey of the phenology of perennial herbs. There we found flowering individuals of this genus. Selabintana is located at the southern foot of Mounts Gede and Pangrango, twin volcanoes 2,958 and 3,019 m, respectively, covered with a biodiverse montane forest. A detailed examination of the specimens revealed that they belong to a new taxon. Here, we describe this new species and provide a detailed morphological account. We also include a key to the species of Gastrodia in Java.

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. 

Figure 2. Gastrodia selabintanensis  Tsukaya & A.Hidayat  at the type locality.
A. Gross morphology. B. Lateral inside view of the perianth tube after splitting the sepals. C. Front inside view of the column, lip, sepals, and petal after splitting the sepals. D. A flower from the joint of two lateral sepals. E. Opening of the perianth tube.

Scale: A, the diameter of coin is 2 cm. B–D, one grid line = 1 mm. A–E: from Hidayat AH5405 (BO & TI); photographs by H. Tsukaya at the type locality of Selabintana, West Java, Indonesia.   DOI: 10.11646/phytotaxa.273.1.9 

 Hirokazu Tsukaya and Arief Hidayat. 2016. A New Species of Gastrodia (Orchidaceae: Gastrodieae, Epidendroideae) from Java. Phytotaxa 273 (1): 77–80. DOI: 10.11646/phytotaxa.273.1.9