Myriophyllum aquaticum
Myriophyllum quitense
Brazilian water-milfoil, parrot feather, parrot feather watermilfoil, parrot's feather, parrot's-feather water-milfoil, parrot- or water-feather, South American water milfoil, water feather
Andean water-milfoil, waterwort milfoil, waterwort water-milfoil
branched or unbranched, to 5 m. Turions absent.
often branched, to 3 m. Turions absent.
in whorls of 4–6(–8), homomorphic;
petiole to 9.6 mm; submersed leaves pectinate, oblanceolate to obovate in outline, (20–)25–70(–75) × (4–)5–26(–32) mm, segments (14–)16–36(–40), filiform, longest segment (2–)4–27(–33) mm; emersed leaves becoming unmodified floral bracts.
mostly in whorls of (3 or)4(or 5), sometimes opposite to subopposite, heteromorphic;
petiole 0–4 mm; submersed leaves pectinate to lobed (basalmost leaves opposite to subopposite, reduced, margins entire), ovate to obovate in outline, (3–)5–25(–35) × (2–)3–18(–20) mm, segments (2 or)3–9(–11), linear, ± applanate, longest segment (7–)8–15(–17) mm; emersed leaves pinnatisect to lobed or entire, ovate to oblong in outline, 2–9 × 1–6 mm, margins dentate to minutely serrate.
to 20 cm;
flowers unisexual;
bracteoles cream to stramineous, (0.3–)0.5–1(–1.5) × 0.1–0.3(–0.5) mm, margins subulate to 3-fid.
to 8 cm;
flowers proximally pistillate, medially bisexual, distally staminate;
bracteoles cream, deltate, 0.5–1 × 0.2–0.6 mm, margins dentate to serrate, with glandular tip.
sepals cream, ovate to deltate, 0.7–0.8 ×0.3 mm;
petals yellow, weakly cucullate, (2.3–)2.7–3.1 × 0.8–1.1 mm;
stamens 8, filaments to 1.2 mm, anthers yellow, linear-oblong, (1.8–)2–2.7 × 0.2 mm.
sepals green to cream, ovate to deltate, (0.2–)0.3–0.5(–0.7) × (0.1–)0.2–0.4(–0.5) mm;
petals persistent, ± purple, oblong, 2–3 × 0.5–1.5 mm;
stamens 8, filaments to 0.6 mm, anthers 1.8–2.5 × 0.2–0.6 mm.
sepals cream, lanceolate to deltate, 0.3–0.5 × 0.1–0.2(–0.4) mm;
petals rudimentary or absent;
pistils to 0.8 mm, stigmas white, to 0.3 mm.
sepals cream, deltate, 0.2–0.5 × 0.1–0.4 mm;
petals ± persistent, cream, ± cucullate, elliptic, 0.1–0.5 × 0.2–0.3 mm;
pistils 1.1–2.2 mm, stigmas cream to ± purple, to 0.6 mm.
cylindric to ovoid, shallowly 4-lobed.
cylindric to oblong, 4-lobed.
olive-green to brown, cylindric, 1.7 × 0.6–0.7 mm, narrowly obovate, abaxial surface rounded, ridges, wings and ribs absent.
tan to olive-brown, cylindric to ovoid, 1.5–1.8 × 0.6–0.8 mm, transversely elliptic, abaxial surface rounded, smooth, sometimes with a shallow, longitudinal ridge, wings and ribs absent.
= 42.
Myriophyllum aquaticum
Myriophyllum quitense
In the flora area, Myriophyllum aquaticum is an introduced invasive aquatic species, existing as pistillate populations throughout North America (R. Couch and E. Nelson 1992); it is native to the lowlands of South America (A. E. Orchard 1981). It has an unusual habit among North American species of Myriophyllum, where it is often observed as a robust emergent aquatic along shorelines. It can be found also growing to a depth of 5 m in lakes, with the largest submersed leaves recorded for any North American species of Myriophyllum. The leaves of M. aquaticum are very distinctive, being largely oblanceolate and two to three times as long as broad, with a large number of uniform, short-pinnate segments, often arranged in whorls of six or more.
Myriophyllum aquaticum has been reported from Iowa and Montana; no specimens have been seen that confirm these reports.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The most distinguishing feature of Myriophyllum quitense is the production of relatively large, ovate distal floral bracts with serrate margins. This characteristic is shared only with M. heterophyllum; however, M. quitense has eight stamens and the latter has four.
The proximal submersed leaves of most Myriophyllum species are uniformly pectinate, but those of M. quitense can range from entire or lobed to pectinate. This species often exhibits a pronounced transition from three or four proximal nodes of large, opposite, spatulate or lobed prophylls, to nodes of besomiform whorled leaves having obtriangular laminar surfaces and distal pinnatifid segments resembling those of pectinate leaves. In addition, the unusual grayish blue color of the foliage and whitish rhizomes are useful characteristics for distinguishing submersed vegetative specimens of M. quitense from similar species, such as M. sibiricum.
Myriophyllum quitense has a highly disjunct distribution in North America and South America (A. E. Orchard 1981; O. Ceska et al. 1986). S. G. Aiken (1981) and R. Couch and E. Nelson (1988) suggested that M. quitense was introduced into North America by migratory waterfowl. Both Ceska et al. and M. L. Moody and D. H. Les (2010) regarded it as native to North America. It has been reported from New Brunswick and Prince Edward Island (D. F. McAlpine et al. 2007) and further range extensions would seem likely given the level of disjunction in distribution.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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WildflowerSearch
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- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
