Mountain Spike Rush

The taxonomy of the septate-culmed species here treated as Eleocharis montana and E. ravenelii should be evaluated. According to H. K. Svenson (1957), the type of E. montana from near Bogotá, Colombia, is the mountain extreme of the species; it has swollen culms with no visible septation.

Specimens from Acadia and St. Landry parishes, Louisiana, are intermediate between Eleocharis montana and E. montevidensis.

Plants perennial, densely tufted or mat-forming; rhizomes mostly hidden by culms and roots, fairly long, 3 mm thick, hard, cortex persistent, longer internodes to 3 mm, scales persistent, ca. 8 mm, membranous, slightly fibrous. Culms terete, when dry with few to many blunt ridges, 10–70 cm × 0.5–2 mm, soft to firm, internally hollow with complete transverse septa 2–5 mm apart, usually evident externally except in narrowest culms. Leaves: distal leaf sheaths persistent, not splitting, proximally dark red, distally green or brown, slightly callose, papery, apex obtuse, tooth present, 0.3–1 mm. Spikelets ovoid, 6–21 × 3–4 mm, apex acute to obtuse; proximal scale amplexicaulous, entire; subproximal scale empty or with flower; floral scales appressed in fruit, 100–500+, (15–)30–40 per mm of rachilla, medium brown to colorless, midrib regions greenish to colorless, ovate, 1.5–2.5 × 1–1.5 mm, entire, apex rounded to subacute, carinate in distal part of spikelet. Flowers: perianth bristles 6–8, pale brown, medium stout, from less than 1/2 achene length to sometimes slightly exceeding tubercle, retrorsely spinulose; stamens 1; anthers dark yellow to brown, 0.6–1 mm; styles 3-fid or some 2-fid. Achenes falling with scales, dark green or medium brown, obovoid to obpyriform, biconvex or sometimes some compressed trigonous in same spikelet, lateral angles prominent, abaxial angle absent or evident, not prominent, 0.8–1.1 × 0.7–0.8 mm, neck short or absent, finely cancellate at 10–20X, sometimes finely rugulose, with 15 horizontal ridges in vertical series. Tubercles brown, pyramidal, mostly depressed, 0.2–0.35 × 0.2–0.4 mm.

Ala., Ariz., Fla., Ga., La., Tex.; Mexico; West Indies; Central America; South America.

Fruiting winter–fall.

Fresh temporary or artificial ponds, ditches, burned savannas, swamp margins; 20–90[–2800]m.

Scirpus montanus Kunth in A. von Humboldt et al., Nov. Gen. Sp. 1: 226. 1816; Eleocharis montana var. nodulosa Svenson; E. nodulosa (Roth) Schultes

Eleocharis montana (H.B.K.) R. & S. Syst. Veg
2:153. 1817.
Scirpns montanus H.B.K. Nov. Gen. & Sp. 1 : 226. 1816.
Scirpus iwdulosus Roth, Nov. PI. Sp. 29. 1821 (Brazil.)
Eleocharis nodulosa Schultes in R. & S. Syst. Veg. Mant. 2: 87. 1824.
Eleocharis consangitinea Kunth, Enum. PI. 2: 148. 1837. (Brazil.)
Eleogemis nodnlosus Nees in Mi.rt. Fl. Bras. 2^: 104. 1842.
Eleocharis haematolepis Steud. Syn. Cyp. 79. 1855. (Quito, Ecuador.)
Eleocharis subnodiilosa Steud. Syn. Cyp. 81 1855 (Guatemala.)
Heleocharis chrysocarpa Bock, in Warm. Vidensk. Meddel. 1869: 134. 1870. (Brazil.)
Heleocharis nodulosa var. tenuis Bock. Flora 62: 160. 1879. (Paraguay.)
Eleocharis andesica Clarke, Kew Bull. Add. Ser. 8 : 23. 1908. (Bogota, Colombia.)
Eleocharis Ravenelii Britton ; Small, Flora SE. U. S. 184 1903. (Texas.)
Heleocharis nodulosa var. suhnodulosa Kiikenth. Repert. Sp. Nov. 23 : 192. 1926.
Eleocharis nodulosa var. angulata Svenson, Rhodora 39: 258. 1937. (Guasca, Colombia.)
Eleocharis montana var. nodulosa Svenson ; I. M. Johnston, Jour. Arnold Arb. 25 : 47. 1944.
Erect from a coarse, creeping rootstock; culms green, 1-2 mm. thick, 3-8 dm. high, terete, with numerous, usually conspicuous (sometimes nearly obsolete) transverse septa; sheaths elongate, stramineous (often with a purplish-red base), the truncate, darkened apex with a distinct mucro; spiketets many-flowered, oblong-lanceolate, acuminate, rarely obtuse, 8-15 mm. long; scales appressed to slightly spreading, 2 mm. long, obtuse to acute, scarious throughout, light to dark brown, with a broad hyaline margin, the lowest suborbicular, firmer, and broadly scarious-margined ; anthers 0.8-1 mm. long; style-branches 2 (not infrequently 3) ; achenes 1 mm. long, broadly obovate, biconvex, yellow to brown or olivaceous, distinctly pitted-reticulate ; style-base usually flattened, brown, half as wide as the achene, deltoid, acute, the surface elevated at the junction with the achene-body; bristles ferrugineous, equaling or slightly exceeding the achene, the common base prolonged into a short stipe.
Type locality : Quindiu Pass, near Bogota, in the Middle Cordillera of Colombia.
Distribution: Florida, Louisiana, Texas, Arizona; Mexico to Panama; West Indies; tropical and temperate South America.