Juncus acutiflorus Ehrh. ex Hoffm.
Tall-growing, in loose clumps or in diffuse colonies, sometimes in radiating lines of stems; rhizome stout, far-extending. Stems 30-100 cm high, stiffly erect, without internal transverse septa below inflorescence. Leaves ± compressed, conspicuously transversely-septate across whole width. Inflorescence 1-12 cm long, open, diffuse and spreading, much-branched with numerous small dark brown clusters of 3-12 flowers at end of branches, secondary branches diverging at an acute angle. Tepals 2-2.5 mm long, lanceolate, long-acuminate, outer < inner, often with recurved tips. Stamens 6. Capsule c. 3 mm long, > tepals, gradually tapering to an acute point, red-brown.
S. Nelson - Kohaihai River, near Westport; Westland - Greymouth and Hokitika districts; Canterbury - Springston. Forming large colonies on swampy roadsides and in wet areas. (Eurasia)
First record: [Healy] 1969: 116. Petrie' s specimen recorded by Cheeseman (Man. N.Z.Fl. 1925, 1059) as J. acutiflorus is in fact J. acuminatus.
First collection: "Fairdown, Buller Co., near railway station, Phormium area in swampy hollow", R. Mason and N. T. Moar 1949, 27.1.1953 (CHR 81491).
J. acutiflorus is similar in the tall habit and far-extending rhizomes to J. subnodulosus, but has less widely diverging secondary inflorescence-branches, long-acuminate (not blunt hooded) tepals and stems not transversely septate below the heads.