Najas gracillima

(A. Braun ex Engelmann) Magnus

Beitrage zur Kenntniss der Gattung Najas 23. 1870.

Endemic
Basionym: Najas indica var. gracillima A. Braun ex Engelmann in A. Gray, Manual ed. 5, 681. 1867
Treatment appears in FNA Volume 22.
Revision as of 23:52, 29 July 2020 by imported>Volume Importer
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Stems slightly branched distally, 4.5–48 cm × 0.2–0.7 mm; internodes 0.1–3.2 cm, without prickles. Leaves spreading to ascending with age, 0.6–2.8 cm, lax in age; sheath 0.5–1.5 mm wide, apex truncate; blade 0.1–0.5 mm wide, margins minutely serrulate, teeth 13–17 per side, apex acute with 2–3 teeth, teeth unicellular; midvein without prickles abaxially. Flowers 1–3 per axil, staminate and pistillate on same plants. Staminate flowers in distal axils, 1.5–2 mm; involucral beaks 2-lobed, 0.8 mm; anthers 1-loculed, 1.3 mm. Pistillate flowers distal to proximal on plant, 0.5–2.7 mm; styles 0.3–1.5 mm; stigmas 2-lobed. Seeds not recurved, light-brown, fusiform, 2–3.2 × 0.4–0.7 mm, apex with style situated offat center; testa dull, 3 cell-layers thick, pitted; aeroleareoles regularly arranged in 40 longitudinal rows, not ladderlike, 4-angled, longer than broad, end walls raised. 2n = 24, 36.


Phenology: Flowering summer–fall.
Habitat: Soft water lakes
Elevation: 0–200 m

Distribution

V22 215-distribution-map.jpg

Man., Ont., Nfld. and Labr. (Nfld.), N.S., Ala., Calif., Conn., Del., D.C., Ill., Ind., Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Tenn., Vt., Va., Wis., Eurasia

Discussion

No specimens were seen from in Alberta, Manitoba, or Quebec, but the species is to be expected there.

Najas gracillima is most similar to N. minor, especially in vegetative condition. Najas gracillima, however, can be separated from the latter species by its style arising off-center at the apex of the ovary wall and by its aeroleareoles being longer than broad. Late in the growing season, the leaves of N. minor become recurved; those of N. gracillima do not.

Selected References

None.

Lower Taxa

None.

"elongating" is not a number.

... more about "Najas gracillima"
1.3 cm13 mm <br />0.013 m <br /> (?) +
Robert R. Haynes +
(A. Braun ex Engelmann) Magnus +
Najas indica var. gracillima +
involucral +
2-lobed +
0.8 cm8 mm <br />0.008 m <br /> (?) +
armed +  and 1-veined +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
sharp-tipped +
short-pedunculate +  and sessile +
Man. +, Ont. +, Nfld. and Labr. (Nfld.) +, N.S. +, Ala. +, Calif. +, Conn. +, Del. +, D.C. +, Ill. +, Ind. +, Ky. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Mo. +, N.H. +, N.J. +, N.Y. +, N.C. +, Ohio +, Pa. +, R.I. +, Tenn. +, Vt. +, Va. +, Wis. +  and Eurasia +
0–200 m +
pistillate +  and staminate +
distal;proximal +
1 +  and 3 +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
Soft water lakes +
0.1 cm1 mm <br />0.001 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
light green +  and brown +
red-purple +  and purple +
whorled +, appearing +  and opposite +
submersed +
spreading;ascending +
0.6 cm6 mm <br />0.006 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
serrate to minutely +
Flowering summer–fall. +
not stipitate +
Beitrage zur Kenntniss der Gattung Najas +
longer than broad +
4-angled +  and not ladderlike +
auriculate +  and not auriculate +
light-brown +
0.2 cm2 mm <br />0.002 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
not recurved +
fusiform +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
not persisting +
variously--shaped +
0.5mm;1.5mm +
4.5 cm45 mm <br />0.045 m <br /> (48 cm480 mm <br />0.48 m <br />) +
slender +
0.2mm;0.7mm +
2-4-branched +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Najas gracillima +
species +
caulescent +  and not rhizomatous +
perennial +  and annual +