This book investigates the comprehensive fern-flora of Canada, aiming to provide a detailed catalog and identification guide for botanists and naturalists. George Lawson, a noted botanist of his time, compiles extensive observations and classifications of fern species found across Canadian territories. The work presents a systematic approach to understanding the diversity and distribution of ferns within the region.

As a foundational text in Canadian botany, Lawson's work is recognized for its early and systematic cataloging of the nation's fern species. Its detailed classifications and distributional data have historically served as a crucial reference for researchers and students of Canadian flora. The book's enduring value lies in its contribution to the scientific understanding of the country's botanical heritage.