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Species
Najas minor All.
IUCN
NCBI
EOL Text
Immature plants of Brittle Naiad are difficult to distinguish from the uncommon Thread-Leaf Naiad (Najas gracillima), although the appearance of mature plants for these two species are quite distinct. Mature plants of Brittle Naiad have leaves that are more wide (about 0.5-1.2 mm. across), more brittle, and a darker shade of green than those of Thread-Leaf Naiad; mature plants of Brittle Naiad also have leaves that are more recurved and their teeth are more conspicuous. Another species of this genus, Spiny Naiad (Najas marina), has even wider leaves (up to 2.5 mm. across) than Brittle Naiad and its leaves have teeth that are fewer in number, but larger in size. So far, Spiny Naiad has been found only in Lake County, Illinois, where it is probably adventive. Other common names of Najas minor include Brittle Water Nymph and European Naiad.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Copyright © 2002-2014 by Dr. John Hilty |
Source | http://www.illinoiswildflowers.info/wetland/plants/br_naiad.html |
Stems profusely branched near apex distally, 11--120 cm ´ 0.2--1 mm; internodes 0.5--5.8 cm, without prickles abaxially. Leaves usually recurved with age, 0.5--3.4 cm, stiff in age; sheath 1--3 mm wide, apex truncate to auriculate; blade 0.1--1.2 mm wide, margins conspicuously serrulate, teeth 7--15 per side, apex acute, with 1--2 teeth, teeth multicellular; midvein without prickles abaxially. Flowers 1--2 per axil, staminate and pistillate on same plant. Staminate flowers in distal axils, 1.9--2.2 mm; involucre 2-lobed, beaks 0.4--2.1 mm; anther 1-loculed, 0.3 mm.
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Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200024706 |
"Red List Category & Criteria: Least Concern ver 3.1 Year Assessed: 2010 Assessor/s: Mani, S. Reviewer/s: Lakshminarasimhan, P., Anitha, K., Raghavan, R., Rasingam, L., Gunaga, S. & Molur, S. Contributors: Molur, S. Justification: This species is widespread throughout a wide geographic range. There is no information on its population or major threats. It is however, listed as Least Concern. Conservation Actions: No population conservation information on this species."
License | http://creativecommons.org/licenses/by/3.0/ |
Rights holder/Author | "Molur et al, 2011", IUCN and ZOO 2011, India Biodiversity Portal |
Source | http://indiabiodiversity.org/species/show/259144 |
This submerged aquatic plant is a summer annual about 2-18" long, although on rare occasions it may become up to 36" long. Individual plants become more branched as they age. The glabrous stems are medium green while young, becoming dark green, more stout, and more brittle with age. Pairs and pseudo-whorls of glabrous leaves about 0.5-3.5 cm. in length occur along these stems, particularly toward their tips. Young leaves are 0.2-0.5 mm. across, medium green, and flexible, while older leaves are 0.5-1.2 mm. across, dark green, stiff, and brittle. The older leaves are usually recurved, creating the appearance of leafy rosettes at the tips of stems. Along each side of the leaf margins are 7-15 teeth that are small in size, but conspicuous. At the leaf bases, there are membranous sheaths about 1.0-2.0 mm. long; each sheath is truncate-fringed along its apex. Mature plants are usually monoecious, rather than dioecious, producing sessile unisexual flowers in the axils of their leaves. These flowers are about 2 mm. long. Individual male (staminate) flowers consist of a single stamen, while individual female (pistillate) flowers consist of a single pistil. Both types of flowers are surrounded by a membranous spathe. The blooming period occurs from mid-summer into the fall. The female flowers are replaced by beaked fruits that are ellipsoid-oblongoid in shape, slightly curved, and about 1.5-3.0 mm. long. Each fruit contains a single seed that is a little shorter than the fruit. Individual seeds are longitudinally ribbed and faintly reticulate. The root system is shallow and fibrous. The fragile stems of older plants are easily broken, creating plant fragments that drift with their seeds in water currents to new locations.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Copyright © 2002-2014 by Dr. John Hilty |
Source | http://www.illinoiswildflowers.info/wetland/plants/br_naiad.html |
"Monoecious and dark green, stem lip to 25-30 cm long and up to 1 mm broad, profusely branched particularly in upper part, intemodes without spines. Leaves linear, serrulate to spinose-dentate with 7-25 teeth on each side, apex acute with 1-2 teeth, sometimes with some spines on the back of the midrib. Sheath 1.5-3 mm long as well as broad, short rounded-truncate or spinulose, with 5-8 teeth on each side. Male flowers: solitary, enclosed in a spathe, neck conical or cylindrical and anther 1-thecous. Female flower without spathe, often 2-3 together, style with 2-stigmas. Seeds slightly recurved at apex; areoles broader than long and arranged ladder like."
Population
This species is widespread and abundant throughout its known range and is spreading as an introduction in North America. There is no detailed information available on population size.
Population Trend
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | © International Union for Conservation of Nature and Natural Resources |
Source | http://www.iucnredlist.org/apps/redlist/details/164446 |
"Red List Category & Criteria: Least Concern ver 3.1 Year Assessed: 2010 Assessor/s: Mani, S. Reviewer/s: Lakshminarasimhan, P., Anitha, K., Raghavan, R., Rasingam, L., Gunaga, S. & Molur, S. Contributors: Molur, S. Justification: This species is widespread throughout a wide geographic range. There is no information on its population or major threats. It is however, listed as Least Concern. Conservation Actions: No population conservation information on this species."
License | http://creativecommons.org/licenses/by/3.0/ |
Rights holder/Author | "Molur et al, 2011", IUCN and ZOO 2011, India Biodiversity Portal |
Source | http://indiabiodiversity.org/species/show/259144 |
Habitat and Ecology
Systems
- Freshwater
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | © International Union for Conservation of Nature and Natural Resources |
Source | http://www.iucnredlist.org/apps/redlist/details/164446 |
"Population: It can be locally abundant and dominant in some places. For example, it is one of the major dominant species in East Lake, Hubei (Chen 1984, Wanlian and Xinzhou 1984). Population Trend: Unknown"
License | http://creativecommons.org/licenses/by/3.0/ |
Rights holder/Author | "Molur et al, 2011", IUCN and ZOO 2011, India Biodiversity Portal |
Source | http://indiabiodiversity.org/species/show/259144 |
Flowering class: Monocot Habit: Herb