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Potamogeton crispus, germinating burs. October.
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Fennel-leaved pondweed (Potamogeton pectinatus). Found in fresh, brackish, or salt water, Cape Breton to British Columbia, south to Florida, Texas, and California. Also in Europe (After Britton & Brown)
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Potamogeton crispus (31-32); Potamogeton zosterifolius (33-35). 31, subterranean stem; 32, sprouting bur; 33, winter bud; 34, long section of winter bud; 35, winter bud sprouting
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Potamogeton pectinatus, gigantic form of Dudley, portion of leafy spray showing tubers. November.
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Potamogeton crispus. 20, recumbent branch; 21, spicular bur; 22, denticulate bur; 23, sprouting bur; 24, denticulate bur; 25, spicular bur
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Potamogeton pectinatus. 45, plant developed in aquarium, suspended in water; 46, sprouting seed; 47, same, later stage; 48, seedling about 10 days old, outer testa of seed removed; 49, seedling three weeks old
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Potamogeton crispus, photo micrograph of section through stem of starch-filled vegetative structure; a, cell with starch grains. November.
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Potamogeton pectinatus. 54, gigantic form of Dudley; 55, gigantic form of Dudley; 56, spray, showing cases of chironomids; 57, characteristic vegetative structure, rooting at nodes, May
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Potamogeton crispus, burs in various stages of development. June.
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Potamogeton pectinatus, cross section through stem, showing numerous air spaces.
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Potamogeton crispus. 26, Cutting showing bur development; 27, sprouting bur; 28, shoot with spicular bur at base; 29, similar structure rooting above tip of bur; 30, bur formation at tip of branch
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Potamogeton pectinatus. 50, Gigantic form of Dudley; 51, Gigantic form of Dudley; 52, gigantic form of Dudley; 53, gigantic form of Dudley
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Potamogeton crispus, leaves, showing characteristic leaf mining of chironomids.
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Potamogeton pectinatus, gigantic form of Dudley, erect axis of plant, 5 feet 2 inches tall, bearing runner at base of stem. November.
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Potamogeton pectinatus. 41, Tubers of two successive seasons; 42, terminal portion of subterranean stem; 43, mature portion of rootstock; 44, spray showing fruiting spike and tuberous runners