Robuta

https://archive.org/details/problemsofcytolo00mant

https://www.vedantu.com/question-answer/name-the-four-classes-of-pteridophyta-with-one-class-11-biology-cbse-5fb375b6de1c3232ee30baf9

https://www.aber.ac.uk/en/life-sciences/our-facilities/botany-gardens/pteridophyta/