Najas guadalupensis
Beitrage zur Kenntniss der Gattung Najas 8. 1870.
Stems often profusely branched distally, 11–90 cm × 0.1–2 mm; internodes 0.1–9 cm, without prickles. Leaves spreading with age, 0.3–3.3 cm, lax in age; sheath 1–3.4 mm wide, apex rounded to truncate; blade 0.2–2.1 mm wide, margins minutely serrulate, teeth 18–100 per side, apex rounded to truncateslightly auriculate, with 1–3 teeth, teeth unicellular; midvein without prickles abaxially. Flowers 1–3 per axil, staminate and pistillate on same plants. Staminate flowers in distal axils, 1.5–3 mm; involucral beaks 4-lobed, 0.2–1.3 mm; anther 1- or 4-loculed, 1–1.7 mm. Pistillate flowers in proximal axils, 1.5–4 mm; styles 0.3–1.5 mm; stigmas 4-lobed. Seeds not recurved, yellowish white with purple tinge, fusiform, 1.2–3.8 × 0.4–0.8 mm, apex with style situated at center; testa dull, 3 cell layers thick, pitted; aeroleareoles regularly arranged in 20–60 longitudinal rows, not ladderlike, 4–6-angled, longer than broad, end walls not raised. 2n = 12, 36, 42, 48, 54, 60.
Distribution
Widespread.
Discussion
By having unicellular teeth on the leaf margin, Najas guadalupensis resembles N. flexilis and N. graminea. The seeds of N. guadalupensis are pitted; those of N. flexilis are smooth. The sheaths of N. guadalupensis are rounded to slightly auriculate; those of N. graminea are deeply auriculate.
Subspecies 4 (4 in the flora).
Selected References
None.
Lower Taxa
Key
| 1 | Seeds 3.3–3.8 mm; aeroleareoles of testa arranged in 50–60 longitudinal rows | Najas guadalupensis subsp. muenscheri |
| 1 | Seeds 2.5 mm or less; aeroleareoles of testa in fewer than 50 longitudinal rows. | > 2 |
| 2 | Teeth of leaf blade evident to unaided eye; anthers 1-loculed | Najas guadalupensis subsp. floridana |
| 2 | Teeth of leaf blade invisible to unaided eye; anthers 4-loculed. | > 3 |
| 3 | Leaf blade with 50–100 teeth per side; stems 0.8 mm or less diam. | Najas guadalupensis subsp. guadalupensis |
| 3 | Leaf blade with 20–40 teeth per side; stem 1 mm or more diam. | Najas guadalupensis subsp. olivacea |