Very small or young leaves may be atypical in shape; fully grown mature leaves should be examined whenever possible.
1. Leaves usually spreading (± prostrate or horizontal), with distinctly round to subreniform blades (at least as broad as long, excluding tentacles and slightly expanded summit of petiole); pollen (and hence mature fresh anthers) white; seeds at least 4 times as long as broad, finely striate but otherwise smooth.
D. rotundifolia
1. Leaves ± ascending or erect, with linear to obovate blades longer than broad; pollen (and hence fresh mature anthers) orange; seeds various (elongate only in D. anglica, with rough surface).
2. Blades of leaves linear (parallel-sided), 7–20 (–25) times as long as wide.
D. linearis
2. Blades spatulate-obovate or cuneate, 2–6.5 times as long as wide.
3. Scape strictly erect, arising centrally from base of plant; petioles at least sparsely pubescent or glandular; blades 3–8 mm wide.
D. anglica
3. Scape arising laterally from base of plant before curving upward; petioles glabrous; blades 2–4 mm wide (excluding spreading, stalked glands).
D. intermedia
All species found in Drosera
Citation:
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 2, 2021. https://michiganflora.net/genus.aspx?id=Drosera.