5. Colocasia Schott, Melet. Bot. 18 (1832).
By: Himanchal T. Magar & Mohan Siwakoti
Taxon Description
Perennial, evergreen herbs. Stout underground corm or short above ground stem, latex bearing, sometimes stoloniferous. Petioles sheathing below; leaves several; leaf blade symmetrically peltate, base usually cordate, apex epinasty. Monoecious. Spathe with lower part persistent enclosing female part of spadix; upper part a deciduous blade. Spadix: basal part female, sometimes separated from male part by sterile flowers. Spadix appendix persistent. Flowers lacking perianth; flowering with leaves. Synandria of 3–6 fused stamens, anthers subsessile, locules horseshoe-shaped in cross section, dehiscing by semi-circular apical pores. Ovary 1-loculed, ovules many, placentation parietal, stigma sessile, sometimes extended upwards into a point. Berries obconic to oblong, many seeded. Seeds ovoid to ellipsoid, endosperm copious.
Taxon Statistics
Worldwide eight species: tropical and subtropical Asia. Three species in Nepal.
Key to Species
1a Leaf blades more than 20 cm. Spathe blade over 10 cm. Spadix appendix shorter than or equaling male section of spadix …………………………. 2. C. esculenta
b Leaf blades smaller than 20 cm. Spathe blade under 6 cm. Spadix appendix about equaling fertile zone(male and female) part of spadix ………………………… 2
2a Leaves thick-textured. Neuter zone absent ……………………….………………………………………..………………………………………………………………………………………… 3. C. fallax
b Leaves usually thin. Female part separated from male part by narrow zone of sterile flowers ………………………..……….………………………………………….. 1. C. affinis
1. Colocasia affinis Schott, Bonplandia.7:28 (1859).
Colocasia bicolor C.L. Long & L.M. Cao.
Perennial stoloniferous herbs up to 30 cm. Tubers ca. 1 cm diam., erect. Stolons ca. 1 mm diam. Leaves 3–7, petioles whitish green, 12–27 cm, sheathing for almost half length; sheaths yellowish-green; leaf blade ovate to cordate, 8–17.5 X 3.3–9.5 cm, thin-textured, pale green with large purple spots, base shallowly cordate (sinus 2–10 mm), apex apiculate. Peduncles pale green, much shorter than petiole, 6.5–10 cm. Spathe green, constricted, 1.5–2.5 X 0.5–1.5 cm; limb oblong-lanceolate, ca. 4.5 cm. apex acuminate. Spadix almost equaling or slightly shorter than spathe, female zone light green, ca. 8 X 3 mm, neuter zone 3–5 mm, male zone 1–1.5 cm; appendix reddish purple, 1.5–2.5 X ca. 0.3 cm, shorter and stouter, apex obtuse, smooth.
Distribution: Nepal, E Himalaya, Assam-Burma, S Asia and E Asia.
Altitudinal range: ca. 2000 m.
Ecology: Wet and shady places.
Flowering: July–August. Fruiting: July–August.
Specimens are not available in KATH. Morphological character is described from specimens deposited in E (Barcode-E00634965) and floral characters taken from the Flora of Bhutan.
2. Colocasia esculenta (L.) Schott, Melet. Bot. 1:18 (1832).
Arum esculentum L. Sp. Pl. 2: 965 (1753); Arum colocasia L.
कर्कलो (Nepali).
Perennial stoloniferous herbs up to 80 cm. Corms 3–5 cm diam., vertical to horizontal. Stolons present or absent. Leaves 2–3, rarely more than 3, petioles green, 30–75 cm, sheathing for half to one-third length; sheaths green; leaf blade oblong-ovate to suborbicular, 20–40 X 13–33 cm, glaucous and waxy, base shallowly cordate (sinus 1–4 cm), apex broadly and shortly cuspidate. Peduncles green, shorter than petiole, 16–26 cm. Spathe creamish, 3–5 X 1.2–1.5 cm; limb cream to golden yellow, narrowly lanceolate, 10–19 X 2–5 cm, apex acuminate. Spadix shorter than spathe, female zone ca. 1.2 X 3.5 cm, neuter zone 1.2–2 cm, male zone 4.5–6.5 cm; appendix pale yellow, 1.5–4.5 cm X ca. 2 mm, shorter than or equaling male zone, apex obtuse, rough.
Distribution: Nepal, E Himalaya, Assam-Burma, S Asia, E Asia and SE Asia.
Altitudinal range: 300–1200 m.
Ecology: Moist ground, marshy places, shady, cultivated land.
Flowering: July–September. Fruiting: July–September.
Whole plant used as food and fodder (Manandhar 2002; Niraula & Singh 2010).
3. Colocasia fallax Schott, Bonplandia. 7: 28 (1859).
Colocasia fallax var. purpurea H.Ara & M.A.Hassan.
Perennial stoloniferous herbs up to 30 cm. Corms ca. 1 cm diam. Stolons ca. 3 mm diam. Leaves 3–8, petioles green, 10–25 cm, sheathing for almost half length; sheaths reddish brown; leaf blade narrowly oblong-ovate, 6–17 X 5.5—11 cm, slightly gaucous, base shallowly cordate (sinus 0.2–1 cm), apex apiculate. Peduncles green, shorter than petiole, 6.5–17 cm. Spathe green at the base, orange-yellow above, appressed, 5–6 cm; limb narrowly lanceolate, apex finely acuminate. Spadix as long as spathe, female zone 12–14 X ca. 5 mm, neuter zone absent, male zone 11–14 X ca. 4 mm; appendix yellow, 2.5–2.7 cm X ca. 1 mm, apex acute, scaly rough.
Distribution: Nepal, E Himalaya, Tibetan Plateau, Assam-Burma, S Asia, E Asia and SE Asia.
Altitudinal Range: 400–2000 m.
Ecology: Wet and shady places.
Flowering: May–July. Fruiting: May–July.
Leaves and corms are used as vegetables (Acharya & Acharya 2010).