Tripleurospermum maritimum

(Linnaeus) W. D. J. Koch

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

Common names: False mayweed
Basionyms: 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.

Distribution

V19-957-distribution-map.gif

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

Discussion

Subspecies 3 (2 in the flora).

Selected References

None.

Key

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
not tailed +  and obtuse +
scarious +
indeterminate +  and determinate +
Luc Brouillet +
(Linnaeus) W. D. J. Koch +
decurrent +
Matricaria maritima +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
compound +  and simple +
lobed;oblong +
False mayweed +
zygomorphic +, actinomorphic +  and (3-)5-merous +
1.6 cm16 mm <br />0.016 m <br /> (2 cm20 mm <br />0.02 m <br />) +
yellow +  and white +
1 cm10 mm <br />0.01 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
winged +  and monomorphic +
brown +, pale +  and dark blackish +
compressed +  and trigonous +
fertile +  and bisexual +
2.5 cm25 mm <br />0.025 m <br /> (?) +
fertile +  and bisexual +
Man. +, N.B. +, N.S. +, N.W.T. +, Nfld. and Labr. (Nfld.) +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +, Calif. +, Maine +, Mass. +, Pa. +  and Eurasia +
glabrous +  and hairy +
tuberculate +  and rugose +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
hemispheric;patelliform +
sessile +  and petiolate +
cauline +  and basal +
deltate +
entire +  and dentate +
pale +  and dark-brown or blackish brown +
0.2mm +  and 1mm +
2-carpellate +
persistent +
28 +  and 60 +
Syn. Fl. Germ. Helv. ed. +
bearing subulate enations +, hairy +  and bristly +
convex;conic +
separated +  and contiguous +
3 +  and 5 +
exalbuminous +
1 +  and 5 +
appendaged +  and truncate +
papillate +
Chamomilla maritima +
Tripleurospermum maritimum +
Tripleurospermum +
species +
campanulate +
cylindric +
0.4 cm4 mm <br />0.004 m <br /> (2 cm20 mm <br />0.02 m <br />) +
serrate +  and crenate +
50 cm500 mm <br />0.5 m <br /> (80 cm800 mm <br />0.8 m <br />) +
10 cm100 mm <br />0.1 m <br /> (50 cm500 mm <br />0.5 m <br />) +
shrub +  and subshrub +