Field book of western wild flowers, New York, 1915, identification, West US, wildflowers, Margaret Neilson Armstrong, Margaret Neilson Armstrong, Carduus californicus, thistles, Carduus candadissimus, women in science, The illustration features two varieties of thistles, noted for their distinctive spiky appearance and serrated leaves. The larger thistle on the left displays a prominent, rounded flower head surrounded by elongated, sharp bracts, while the one on the right exhibits a more elongated flower structure. Both plants are labeled with their scientific names: 'Carduus Californicus' and 'C. candadissimus.' The intricate detailing captures the textures of the leaves and the unique shapes of the flower heads, highlighting the natural beauty and complexity of these botanical specimens.