NAS - Nonindigenous Aquatic Species
Dawson, F.H., and E.A. Warman. 1987. Crassula helmsii (T. Kirk) Cockayne: Is it an aggressive alien aquatic plant in Britain? Biological Conservation 42(4):247-272. https://doi.org/10.1016/0006-3207(87)90071-1.
Reference Number: 29340 Type: Journal Article Author: Dawson, F.H., and E.A. Warman Date (year): 1987 Article Title:Crassula helmsii (T. Kirk) Cockayne: Is it an aggressive alien aquatic plant in Britain? Journal Name: Biological Conservation Volume: 42 Issue: 4 Pages: 247-272 URL: Keywords: Crassula helmsii, New Zealand pygmyweed, swamp stonecrop DOI: 10.1016/0006-3207(87)90071-1
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Citation information: U.S. Geological Survey. [2026]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [1/13/2026].
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