posticous vs rearwards

posticous

adj

  • posterior 

  • Situated on the outer side of a filament; said of an extrorse anther. 

rearwards

adj

  • Rearward. 

adv

  • Rearward. 

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