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FOC | Family List | FOC Vol. 23 | Hydrocharitaceae | Najas

1. Najas marina Linnaeus, Sp. Pl. 2: 1015. 1753.

大茨藻 da ci zao

Stems 30-100 cm or more tall, 1-4.5 mm in diam., mostly armed with spines, spines sometimes absent except apically. Leaves 1.5-3 cm × 2-3.5 mm, fleshy, abaxial side of midvein usually with spines; sheath ca. 3 mm, entire or serrulate with 1-3 spine cells on upper side without auricle, leaf acute at apex, with 2-10 conspicuous teeth on each side of margin; teeth 1-2 mm. Plants dioecious; flowers yellowish green. Male flowers ca. 5 × 2 mm; spathe with a short neck; anther 4-thecous. Female flowers 2-4.5 mm; style ca. 1 mm; stigmas 2- or 3-lobed. Fruit elliptic to obovoid-elliptic, 4-6 × 3-4 mm. Seeds ovoid; testa pitted; areoles polygonal, irregularly arranged. Fl. and fr. Sep-Nov. 2n = 12*, 24, 48, 60*.

Ponds, lakes, slow-moving rivers; below 2700 m. Anhui, Guangdong, Guangxi, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Shandong, Shanxi, Taiwan, Xinjiang, Yunnan, Zhejiang [India, Japan, Kazakhstan, Korea, Kyrgyzstan, Malaysia, Mongolia, Myanmar, Pakistan, Russia, Sri Lanka, Tajikistan, Turkmenistan, Uzbekistan, Vietnam; Africa, SW Asia, Australia, Europe, North and South America].

1 Stems without spines except at apex; abaxial side of leaf midvein without spines.   1c var. brachycarpa
+ Stems with spines; abaxial side of leaf midvein with spines   (2)
2 (1) Seeds 2.5-4 mm; style and stigma. 2-1.4 mm; anther 1-3.3 mm.   1d var. intermedia
+ Seeds 4-6 mm; style and stigma 2-3 mm; anther ca. 4 mm   (3)
3 (2) Margins of leaves with 4-10 conspicuous teeth; stems with spines.   1a var. marina
+ Margins of leaves with 2 or 4 teeth; stems with only 1 or 2 spines under nodes.   1b var. grossidentata

Lower Taxa


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