cowslip vs moonwort

cowslip

noun
  • A low-growing plant, Primula veris, with yellow flowers. 

  • Primula deorum, a flowering plant known as God's cowslip and rila cowslip 

  • Primula florindae, a flowering plant known as giant cowslip and Tibetan cowslip 

  • marsh marigold, Caltha palustris, a plant in the buttercup family, growing in wet, boggy locations. 

  • Pulmonaria angustifolia, blue cowslip or narrow-leaved lungwort 

  • Primula sikkimensis, a flowering plant known as Himalayan cowslip and Sikkim cowslip 

moonwort

noun
  • A small fern, Botrychium lunaria (lesser moonwort); later, any member of the genus. 

  • Lunaria annua (greater moonwort); also known as Honesty and Actual Honesty. 

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