Tripleurospermum maritimum

(Linnaeus) W. D. J. Koch

Syn. Fl. Germ. Helv. ed. 2, 1026. 1845.

Common names: False mayweed
Basionym: Matricaria maritima Linnaeus Sp. Pl. 2: 891. 1753
Synonyms: Chamomilla maritima (Linnaeus) Rydberg
Treatment appears in FNA Volume 19. Treatment on page 550. Mentioned on page 548, 549.

Perennials (sometimes biennials), 10–50(–80) cm. Stems 1–5+, usually procumbent, sometimes ascending (± erect), branched distally, glabrous or sparsely hairy. Leaf blades 2–8 cm, ultimate lobes ± cylindric, 4–20 mm, ± fleshy, apices obtuse or mucronate. Heads (3–)10–50 in corymbiform arrays or borne singly. Phyllaries centrally dark greenish or brownish, oblong to narrowly triangular or broadly triangular, unequal, scarious margins pale to dark brown or blackish brown, 0.2–1 mm wide. Ray florets 10–34+; corollas 10–16[–20] mm. Disc corollas ca. 2.5 mm. Cypselae pale to dark blackish brown, ribs ± contiguous or separated by less than 1/4 their widths (1–2 supernumerary ribs sometimes present), abaxial-apical resin glands elongate (lengths 2+ times widths), abaxial faces transversely rugose, minutely roughened on faces and between ribs. 2n = 18, 36.



Man., N.B., N.S., N.W.T., Nfld. and Labr. (Nfld.), Nunavut, Ont., Que., Yukon, Alaska, Calif., Maine, Mass., Pa., Eurasia.


Subspecies 3 (2 in the flora).

Selected References



1 Phyllaries oblong or narrowly triangular, scarious margins pale to dark brown, 0.2–0.4 mm wide; cypselae: resin gland lengths often much more than twice widths; coastal ne North America Tripleurospermum maritimum subsp. maritimum
1 Phyllaries broadly triangular, scarious margins blackish brown, 0.4–1 mm wide; cypselae: resin gland lengths usually little more than twice widths; coastal arctic Tripleurospermum maritimum subsp. phaeocephalum
Luc Brouillet +
(Linnaeus) W. D. J. Koch +
Matricaria maritima +
False mayweed +
Man. +, N.B. +, N.S. +, N.W.T. +, Nfld. and Labr. (Nfld.) +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +, Calif. +, Maine +, Mass. +, Pa. +  and Eurasia. +
Syn. Fl. Germ. Helv. ed. +
Chamomilla maritima +
Tripleurospermum maritimum +
Tripleurospermum +
species +