Y.I. Lee, hybr. nov.—TYPE: TAIWAN, Hsinchu County, Jiashih Township, Niao Zui Shan, elev. ca. 1,500 m, 25 Mar 2008, Yung-I Lee 200902 (holotype: TNM). 新竹根節蘭. Figures 1 and 2.
Hybrida natunali e C. arisanensi et C. sieboldii genita, forma foliorum, diam. radicum, labellis, calcaribus et fructibus omnino inter C. arisanensem et C. sieboldii, ab ambabus plantis 40–60 cm altis, floribus 4–5 cm diam, cremeo-flavidis differt.
Plants 40 – 60 cm tall. Pseudobulb globose-ovoid, 3 cm long, 2 cm in diam, with 3 or 4 nodes. Leaves 3 – 4, elliptic to narrow elliptic, apex acuminate, leaf blade 35 – 40 cm long, 6.5 - 9 cm wide, not fully opened at anthesis, petiole 5 – 10 cm long (Figure 3). Inflorescence raceme with 7 to 10 flowers arising with developing leaves and pseudobulbs, about 50 – 70 cm long, 4.2 – 4.9 cm wide; pedicel with ovary light green, about 2 cm long, ovary shortly pubescent; floral bracts lanceolate, 1 – 1.5 cm long. Flowers 4 – 5 cm across, creamy yellow; lip with brighter yellowish lobes. Dorsal sepal lanceolate-ovate, 2.5 – 3 cm long, 1.2 cm wide, acuminate at apex, slightly contracted at base; lateral sepals similar, slightly oblique, 2.7 – 3.2 cm long, 1.2 cm wide. Petals oblanceolate, 2 – 2.4 cm long, 0.5 cm wide, acuminate at apex. Lip deeply 3-lobed, 2 cm across, adnate to column at base, spurred; lateral lobes, broadly flabellate or ovate; central lobe oblong, margins undulate, apex emarginate with short aristate; disc with 2 short ridges and 3 slender, long ridges, the basal disc adjacent to column with 2 rows of dense white hairs. Spur white, curved, shortly pubescent 8 – 12 mm long. Column stout, 7 mm long. Anther 5 mm long, cordate; pollinia clavate, orange, 2 mm long, with short caudicles attached to viscidium; stigma solitary; rostellum bifid, acute at apex. Capsule with 6 lightly longitudinal ridges, 4.8 – 5.2 cm long, 1.6 – 2 cm wide. The seeds numerous, fusiform with white and transparent seed coat. The seed size about 750 μm long, 100 μm across (Figure 4). The somatic chromosome number of C. xhsinchuensis is 2n = 40 that is the same as its putative parents (Tanaka et al., 1981) (Figure 5).
It is known mainly from the mountain area in Jiashih Township (1500 m) of Hsinchu County in northern Taiwan.
The name of this species is derived from the Hsinchu County, the place of its discovery in northern Taiwan.
C. xhsinchuensis only occurs at the sites where both C. arisanensis and C. sieboldii could be found together. Base on the comparison of morphological characteristics of reproductive and vegetative organs of C. xhsinchuensis and its putative parental species (Table 1, Figures 2, 3 and 6), it is proposed that this unusual plants occur in Jiashih Township of Hsinchu County is a natural hybrid between C. arisanensis and C. sieboldii.
The root diameter of C. xhsinchuensis shows an intermediate condition between its putative parents (Table 1; Figure 6). The root diameter of C. arisanensis (Figure 6B) is the thickest among the three species, whereas the root diameter of C. sieboldii (Figure 6C) is the thinnest. The velamen of C. xhsinchuensis is 4 to 5 celled-wide, and the cortex is 8 to 9 celled-wide (Figure 6A). The hyphae, and pelotons could be found in the cells of the cortex. The other features, including leaf shape (Figure 3) and flower color (Figures 2A,D and G) of C. xhsinchuensis are intermediate between those of C. arisanensis and C. sieboldii. The spur shape of C. xhsinchuensis is curved that is similar to the spur shape of C. arisanensis; while the ovary color of C. xhsinchuensis is light green that is similar to the ovary color of C. sieboldii (Figures 2B,E and H). The capsule shape of C. arisanensis is characterized by having 6 longitudinal wing-like ridges, while C. sieboldii has no conspicuous wing-like ridges on its capsule. C. xhsinchuensis has 6 lightly longitudinal ridges on the capsule, showing an intermediate condition (Figures 2C,F and I).