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發表於 2011-10-25 17:10:19
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阿凡达 發表於 2011-10-25 17:08 
金鱼藻（学名：Ceratophyllum demersum L.）是悬浮于水中的多年水生草本植物，植物体从种子发芽到成熟均 ...
Ceratophyllum demersum (Rigid Hornwort or coontail) is a species of Ceratophyllum, with a cosmopolitan distribution in temperate and tropical regions.
It is a submerged, free-floating aquatic plant, growing in still or very slow-moving water in ponds and streams with summer water temperatures of 15-30 °C and a rich nutrient status, rooting in mud at the bottom of the water. The stems reach lengths of 1–3 m, with numerous side shoots making a single specimen appear as a large, bushy mass. The leaves are produced in whorls of six to twelve, each leaf 8–40 mm long, simple, or forked into two to eight thread-like segments edged with spiny teeth; they are stiff and brittle. It is monoecious, with separate male and female flowers produced on the same plant. The flowers are small, 2 mm long, with eight or more greenish-brown petals; they are produced in the leaf axils. The fruit is a small nut 4–5 mm long, usually with three spines, two basal and one apical, 1–12 mm long. Plants with the two basal nut spines very short are sometimes distinguished as Ceratophyllum demersum var. apiculatum (Cham.) Asch., and those with no basal spines sometimes distinguished as Ceratophyllum demersum var. inerme Gay ex Radcl.-Sm |
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在線雷達
發表於 2011-10-24 21:15:00
