Malabar spinach vs water spinach

Malabar spinach

noun
  • Basella alba, an Asian vine with leaves that are used as spinach-like greens. 

water spinach

noun
  • Basella alba, Malabar spinach, with thick, succulent, heart-shaped leaves 

  • Ipomoea aquatica, a green leafy vegetable used as a food in several cuisines of East and Southeast Asia 

  • Amaranthus dubius, often bearing red or purple marks 

  • Amaranthus tricolor, edible amaranth 

How often have the words Malabar spinach and water spinach occurred in a corpus of books? (source: Google Ngram Viewer )