1. Plant Systematics Third Edition An Intergrated Approach- Gurcharan Singh
archive.org/details/PlantSystematicsThirdEditionAnIntergratedApproach
2. Practical Plant Identification- James Cullen
www.pdfdrive.com/practical-plant-identification-including-a-key-to-native-and-cultivated-flowering-plants-in-north-temperate-regions-e158778348.html