Cryptocoryne isae

Cryptocoryne isae Wongso, sp. nov. Fig. 810.

Holotype: Indonesia, W Kalimantan, Schwaner mountains, Sekadau Regency, S of Sekadau, 19 Aug 2015, S. Wongso SW 1561 (BO; isotypes: C, L).

Diagnosis Cryptocoryne isae usually has fewer than 10 upright leaves to 25 cm long, with a green, narrowly ovate, somewhat spongy blade, which could resemble C. zaidiana; the c. 6 cm long spathe has a short, forward obliquely twisted, purple limb with an indistinct, darker collar, whereas C. zaidiana has a long-tubed spathe with a broad, white, rugose limb and a purple throat. Its chromosome number of 2n = 10 has hitherto not been recorded for Cryptocoryne.

Description Amphibious herbs, c. 20 cm tall. Rhizome thick, firm, notched, with long, stout, subterranean stolons. Leaves usually less than 10 together in a rosette, 20-25(-30) cm long, blade erect-spreading from an upright petiole, dark green, lighter green abaxially, narrowly ovate, 2-3 5-10 cm, thick, softly spongy, smooth, margin entire, smooth or with fine crenulations. Cataphylls whitish brownish, c. 3 cm long, 2-keeled, usually reaching soil surface. Peduncles 1 or 2, to 8 cm long. Spathe c. 6 cm long, whitish outside in proximal part, distal purplish; kettle ovate-cylindric, slightly constricted below level of male flowers, to 2.5 cm long, white inside, flap light yellow; tube c. 1 cm long, white inside; limb forward obliquely twisted, to 3 cm long, purple with an indistinct, darker collar, rather smooth, red colour continuing a few mm into tube. Spadix to 3 cm long, usually with 5 whitish female flowers with broadly ellipsoid to emarginate stigmas with a slight purplish tinge along stigmatic margins; olfactory bodies yellow, rounded; male flowers 3040, yellowish. Syncarp ovoid with persistent stigmas. Seeds with germinating embryo emerging c. ⅓ from distal end with c. 5 plumulary processes.

Chromosome number 2n = 10, reported here for SW 1561.

Distribution Probably endemic to W Kalimantan, Schwaner mountains, Sekadau Regency, S of Sekadau, where it has been observed in one locality besides the type locality.

Ecology The plants that provided the type specimens were found among other herbs emerging from low-lying forest floor in the upper, drier areas near a stream with a loamy, muddy substrate; the long petiole may be an adaptation to tree leaf accumulation rather than to deep water or substrate sedimentation. The short spathe on a short peduncle situated between the proximal parts of the petioles indicates that plants are always emergent during the flowering season at this site.

A second known locality is reported SW of the type locality. This locality has a higher water level; the peduncle is longer (more than 6 cm). Unfortunately, this site will be opened for agriculture soon. The type locality was also somewhat disturbed, with only secondary forest present. Altitude 125 m.

Eponymy Named after Isa Bin Ipor, of UNIMAS, who has studied the Cryptocoryne species of Sarawak for many years and more recently has joined explorations for species in Kalimantan.

Remarks Chromosome number 2n = 10. This surprisingly low number is new in Cryptocoryne. Comparable low chromosome numbers have recently been recorded in the SE Asian Araceae genus Typhonium (Wang & al. 2002; Dao & al. 2007; Sousa & al. 2014).