Najas marina L.

Holly-leaved naiad (en), Grande naïade (fr), Naïade majeure (fr), Naïade marine (fr)

Species

Angiosperms > Alismatales > Hydrocharitaceae > Najas

Characteristics

Plant up to c. 70 cm, lower internodes 3-8 cm by 0.9-2.6 mm, glabrous to very spiny. Leaves 0.5-4.5 cm by 1.5-3.5 mm, flat, sometimes triangular in section, almost always fleshy; tip acute to blunt (blade c. 3 mm below the tip 1.8-3 mm wide); margin on either side with 5-12(-40) spiny teeth; dorsal surface sometimes without, often with 1-6(-40) spines; teeth up to long triangular or conical; up to as long as the width of the blade; spine cells 0.05-0.15 mm, brownish; midrib c. 0.1 as wide as the blade, cavities occupying up to 3/4 of the leaf-width, septa indistinct. Sheath on either side (without or) with 1-5(-10), mostly inconspicuous spines, 2-6½ by 3-9 mm; auricles absent or up to c. 0.2 mm long. Flowers solitary. Spathe of male flower (in Mal. unknown) c. 4.5 mm long (Kashmir specimens); neck about cylindrical, 0.3-0.5 mm, edge somewhat lobed, sometimes with (?3) spines; anther 4-celled, c. 3.5 by 2.5 mm; 'perianth lobes' rather indistinct; 'pedicel' c. 0.5 mm, in anthesis longer. Spathe in female flower absent; female flower 1.9-3.8 mm, ovary 0.8-1.2 by 0.6-0.8 mm, style 0.2-0.8 mm, with 2-4 stigmas 0.9-2 mm. Seeds (asymmetrical) elliptical to ovate, narrowing to the tip, somewhat compressed, (3.5-)4-4.4(-7) by (2-)2.4-2.6 mm; testa shiny with rather irregularly arranged ± isodiametrical, 5-6 angular, unequal-sized areoles.
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Stems up to 150 cm. long, up to 2 mm. in diameter, mostly armed with spines.. Leaves 3.6-65 mm. long, fleshy, acute, 1.1-5.7 mm. wide including teeth on both sides (or 0.4-2.5 mm. excluding the teeth); margin on each side serrulated with (0-)4-17(-40) conspicuous spiny teeth on broad triangular excrescences, the spine-cell resting upon several elongate brown cells; teeth up to 2 mm. long, the ratio of teeth-length to leaf-width being 0.4-2.5; abaxial side of midrib with (0-)2-8(-40) spines, similar to those on the margin and on the stem; septa and fibres always absent; sheath 1.5-5 × 1-5.5 mm. (ratio = 0.4-1.2), rounded, entire or serrulated with 1(-3) spine-cells on each side.. Inflorescences axillary, solitary.. Male flower 2-5 (including spathe-neck) × 0.8-3 mm.; neck of the spathe 0.5-1 mm., tapering at the top, bearing brownish spine-cells at the apex; inner envelope protruding 0.2-0.7 mm. above the anther; anther 1.2-4 × 0.7-2.5 mm.. Female 2-5 mm. long; ovary 1-3.5 × 0.3-1.9 mm.; style and stigma 0.3-1.6 mm.; stigma (2-)3(-4)-lobed.. Fruit with persistent membranous pericarp and remnants of style.. Seed ovate, slightly asymmetrical, 1.9-7.5 mm. × 0.8-3.3 mm. (ratio = 1.2-3.5); testa pitted with areoles, arranged irregularly; areoles irregular in shape and dimensions.
Stems branched distally, 6--45 cm ´ 0.5--4 mm; internodes 0.3--11 cm, usually with prickles. Leaves spreading to ascending with age, 0.5--3.9 cm, stiff in age; sheaths 2--4.4 mm wide, apex acute; blade 0.4--4.5 mm wide, margins coarsely serrate, teeth 8--13 per side, apex acute, with 1 tooth, teeth multicellular; midvein with prickles abaxially. Flowers 1 per axil, staminate and pistillate on different plants. Staminate flowers in distal to proximal axils, 1.7--3 mm; involucral beaks 2-lobed, 0.3--0.7 mm; anthers 4-loculed, 1.7--3 mm. Pistillate flowers in distal to proximal axils, 2.5--5.7 mm; styles 1.2--1.7 mm; stigmas 3-lobed. Seeds not recurved, reddish brown, ovoid, 2.2--4.5 ´ 1.2--2.2 mm, apex with style situated at center; testa dull, 10--15 cell layers thick, pitted; areoles irregularly arranged, not in distinctive rows, not ladderlike, 3--4-angled, longer than broad, end walls slightly raised. 2n = 12 (Europe).
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*.
Submerged, dioecious, robust annual, to 3 m long. Stems to 2 mm diam.; internodes spinescent. Leaves linear, flat, to 5 cm long, to 5 mm wide (including spines), acute; septa and fibres always absent; margins with numerous large multicellular spine-tipped teeth to 2 mm long; midrib usually with similar teeth; sheath without auricles. Male flowers spatheate, 3–4 mm long; anther 1–3 mm long, tetrasporangiate. Female flowers espatheate, 3–4 mm long; ovary 1–3.5 mm long; style and stigma 0.3–1.6 mm long; stigma usually 3-lobed. Seed usually 3–6 mm long, with remnants of style attached; testa with irregularly arranged areoles.
A water plant. It grows as an annual herb. It grows up to 3 m high. The leaves are 5 cm long by 0.5 cm wide. There are large, spine tipped teeth along the edge. The leaves form a sheath at the base. The flowers are of one sex and occur singly in the axils of leaves. Male flowers have a leafy spathe at the base. The flowers are 3-4 mm long. They have one stamen. The female flowers do not have the leafy spathe. They are 3-4 mm long. Flowering and fruiting take place beneath the water surface.
Dioecious; stems 0.5–4.5 dm, 0.5–4 mm thick, often prickly; lvs 0.5–4 cm × 0.5–4.5 mm, spreading or ascending, prickly along the midvein beneath, coarsely serratewith 8–13 multicellular teeth projecting 0.5–1 mm on each side; anthers dithecal, with 4 microsporangia; seeds 2.2–4.5 mm, reddish-brown, ovoid, pitted, with irregular areolae; 2n=12. Brackish or highly alkaline water of ponds and lakes; irregularly cosmop.; in our range from N.Y. and Pa. to Wis., Ill., and Minn.
Life form annual
Growth form herb
Growth support aquatic
Foliage retention -
Sexuality dioecy
Pollination hydrogamy
Spread hydrochory
Mature width (meter) -
Mature height (meter) 0.5
Root system -
Rooting depth (meter) -
Root diameter (meter) -
Flower color
Blooming months -
Fruit color -
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer -
Photosynthetic pathway c3

Environment

It grows in temperate and tropical places. It grows best in warm places. It grows in lakes with fresh or brackish water. It grows quickly when water temperatures are above 20°C. It can grow in slightly salty water. In Argentina it grows below 500 m above sea level.
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Fresh or brackish water. Ponds, lakes and slowly-moving rivers at elevations up to 2,700 metres in China. Brackish or highly alkaline waters of ponds and lakes to 1,000 metres in America.
Fresh or brackish water. Ponds, lakes and slowly-moving rivers at elevations up to 2700 metres in China. Brackish or highly alkaline waters of ponds and lakes to 1000 metres in America.
In coastal sites and inland; grows in estuaries andlakes with fresh or brackish water. 
Light 4-9
Soil humidity 10-12
Soil texture 1-6
Soil acidity 3-8
Soil nutriment -
Hardiness (USDA) 6-12

Usage

Uses fodder
Edible leaves
Therapeutic use -
Human toxicity -
Animal toxicity -

Cultivation

Can be grown by seedlings.
Mode seedlings
Germination duration (days) -
Germination temperacture (C°) -
Germination luminosity -
Germination treatment -
Minimum temperature (C°) -
Optimum temperature (C°) -
Size -
Vigor -
Productivity -

Images

Habit

Najas marina habit picture by Yoan MARTIN (cc-by-sa)

Leaf

Najas marina leaf picture by Alain Lagrave (cc-by-sa)

Distribution

Najas marina world distribution map, present in Aruba, Australia, Austria, Burkina Faso, Bangladesh, Bulgaria, Bahamas, Belarus, Bolivia (Plurinational State of), Brazil, Botswana, Canada, Switzerland, Chile, China, Cuba, Cyprus, Czech Republic, Germany, Dominica, Denmark, Algeria, Egypt, Eritrea, Spain, Finland, France, Micronesia (Federated States of), Greece, Haiti, Hungary, Indonesia, Iran (Islamic Republic of), Iraq, Italy, Jamaica, Japan, Kazakhstan, Kyrgyzstan, Libya, Morocco, Moldova (Republic of), Madagascar, Myanmar, Montenegro, Mozambique, Mauritius, Malaysia, Namibia, Netherlands, Norway, Oman, Pakistan, Panama, Palau, Poland, Puerto Rico, Korea (Democratic People's Republic of), Portugal, Réunion, Romania, Russian Federation, Rwanda, Saudi Arabia, Senegal, Singapore, South Georgia and the South Sandwich Islands, Sweden, Turks and Caicos Islands, Thailand, Turkmenistan, Tunisia, Taiwan, Province of China, Tanzania, United Republic of, Uganda, Ukraine, United States of America, Uzbekistan, Venezuela (Bolivarian Republic of), Viet Nam, Zambia, and Zimbabwe

Conservation status

Najas marina threat status: Least Concern

Identifiers

LSID urn:lsid:ipni.org:names:321282-2
WFO ID wfo-0000769531
COL ID 45L25
BDTFX ID 43490
INPN ID 109213
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Najas marina Najas gracilis Najas latior Najas marina var. muricata Najas major var. ehrenbergii Najas marina var. angustifolia Najas major var. angustifolia Najas marina var. multidentata Najas major var. multidentata Najas major var. paucidentata Najas marina var. ehrenbergii Najas marina var. bollei Najas marina var. latior Najas marina var. latifolia Najas marina var. paucidentata Najas marina subsp. major Najas marina var. denticulata Najas major subsp. multidentata Najas major subsp. paucidentata Najas marina var. marina Najas major var. laevis Najas marina var. brevifolia

Lower taxons

Najas marina subsp. arsenariensis Najas marina subsp. sumatrana Najas marina var. brachycarpa Najas marina subsp. marina Najas marina var. intermedia Najas marina subsp. commersonii Najas marina var. grossidentata