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Long-beaked arrowhead (Sagittaria longirostra). Found in swamps and along ponds, New Jersey and Pennsylvania to Alabama (After Britton & Brown)
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Potamogeton americanus, spray showing attachment of cases of caddis fly (fam. Leptoceridae).
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Potamogeton obtusifolius, winter buds. October.
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Potamogeton Robbinsii, photo-micrograph of section through old stem, showing arrangement of mechanical tissue.
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Water plantain (Alisma Plantago-aquatica). Found in shallow water or mud throughout North America. Also in Europe and Asia (After Britton & Brown)
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Field of Phyllospadix scouleri.
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Waterweek (Philotria canadensis). Found nearly throughout North America, except extreme north (After Britton & Brown)
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Leafy pondweed (Potamogeton foliosus). Niagra Falls to Michigan and California (After Britton & Brown)
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Warner Parks Nature Center, Nashville, Davidson County, Tennessee, US
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Sagittaria rigida. The leaf in the center is from deep water; that at the right from shallow water near the shore.
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Potamogeton americanus. 1, seed; 2, seedling 5 days old; 3, seedling 14 days old; 4, seedling of four months; A, winter buds; 5, germinating winter bud, natural size; the last two winter buds belated in development. Aquarium specimen, January 24, 1914
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Potamogeton obtusifolius, erect axes bearing winter buds. October.
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Potamogeton Robbinsii, photo-micrograph of section through old stem, showing arrangement of mechanical tissue--Detail.
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Lysichiton camtschatcense with background of Polystichum and Lomaria.
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Potamogeton heterophylius. 12, typical habit of land form; 13, terminal portion of rootstock showing tendency to become tuberous; 14, same, more advanced stage; 15, aquarium specimen
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Potamogeton amplifolius, leaves, showing characteristic mines of Hydrellia.
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Warner Parks Nature Center, Nashville, Davidson County, Tennessee, US
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Potamogeton americanus. 1, seed; 2, seedling 5 days old; 3, seedling 14 days old; 4, seedling of four months; A, winter buds; 5, germinating winter bud, natural size; the last two winter buds belated in development. Aquarium specimen, January 24, 1914; 6, rootstock with winter bud A, natural size. September
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Lesser duckweed (Lemna minor). Found in ponds, lakes, and stagnant waters throughout North America below 58 deg. N..lat. Also in Europe (After Britton & Brown)
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Potamogeton Robbinsii, branch, showing points where dismemberment occurs.
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Potamogeton heterophyllus (16-17); Potamogeton perfoliatus (18-19). 16, aquarium specimen; 17, aquarium specimen; 18, winter shoot showing elongation of internodes; 19, growing tips of same
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Potamogeton amplifolius (7) rootstock; Potamogeton heterophyllus (8); Potamogeton heterophyllus (9-12). 7, rootstock; 8, submerged plant; 9, rootstock not tuberous; 10, tuberous rootstock; 11, tuberous rootstock
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Warner Parks Nature Center, Nashville, Davidson County, Tennessee, US
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Long-leaved pondweed (Potamogeton lonchites). Found in ponds and slow streams, New Brunswick to Washington, south to Florida and California (After Britton & Brown)
