Xanthosoma  tropical aroids grown as ornamentals or for food (leaves, tubers). Tops are frost sensitive, tubers will survive some freezing but not much. Tropical Americas. Araceae. rev 6/2016

robustum    dark foliage    young clump      an evergreen (frost free!) to deciduous tuberous plant, with very dark blue green, arrow-shaped leaves reaching about 24-30" tall. Use it for a tropical-foliage effect on a modest-sized plant. Best in containers, with at least half a day of sun. USDA zone 9 (zone 8?)/Sunset 8-9, 14-24. Mexico. rev 9/2016

sagittifolium 'University of Massachusetts
'  TAIOBA, TANNIA, MAFAFA  arrowhead leaves     mature Huntington specimen   
flower cluster     another Huntington plant, growing partially in water   a large, perennial, tropical foliage shade/part shade plant or full sun row-crop vegetable. In full to half shade leaves can reach 30" long and plants get 3' tall by 4' wide, producing pups from the base to form larger colonies. Much smaller if grown in sun as a row crop. Needs regular watering for best appearance but is surprisingly easy as a container plant, even with full-sized foliage. We first tried this just because we saw it on a TC plug list. The grower knew nothing about it, which is not unusual. Then after more than a decade I stumbled upon a U Mass publication on their Ethnic Crops Program which discussed this South American relative of taro (Colocasia esculenta) and has instructions for growing, harvest and post-harvest handling. I'm trying this myself as a home crop this year (2017), overwintering it exposed and unprotected in a former row-crop field. Central and South America. USDA zone 9/Sunset 8-9, 14-24.rev 10/2017