Scirpus.]
CYPERACEÆ.
771
A somewhat heterogeneous aspemblage of about 130 species, found in all parts of the world, both tropical and temperate. Of the 13 species found in New Zealand, 4 are generally disitributed in both the Northern and Southern Hemispheres; 6 extend to Australia, 3 of them reaching South Africa as well; 1 is found in Tristan d'Acunha; the remaining 2 are endemic. The student will find it a difficult and perplexing task to discriminate between several of the species of the first section.
| Section I. Isolepis. Usually small and slender plants. Spikelets in clusters or solitary. Hypogynous bristles wanting. | |
| * Spikelets solitary or 2–3 in a head. | |
| Stems long, slender, often much branched and floating. Spikelet solitary. Style-branches 2. Nut biconvex, white | 1. S. lenticularis. |
| Stems very short, ⅛–½ in. long, leafy. Spikelets usually solitary, concealed by the leaves. Style-branches 2. Nut biconvex, brown | 2. S. basilaris. |
| Stems 1–6 in., branched below. Leaves several, equalling the stems. Spikelets 1-2. Style-branches 3. Nut obovoid, obtusely trigonous, white | 3. S. aucklandicus. |
| Stems 2–6 in. Leaves 1–2, shorter than the stems. Spikelets 1–3. Style-branches 3. Nut obovoid, obtusely trigonous | 4. S. cernuus. |
| ** Spikelets usually more than 3 in a cluster (sometimes reduced to 1 in small states of S. antarcticus and S. inundatus). | |
| Stems ½–6 in. Leaves 1–3, often rigid and cartilaginous. Spikelets 1–9; glumes rigid, keeled, grooved on the sides. Stamens 3. Style-branches 3. Nut acutely trigonous, yellow to dark-brown | 5. S. antarcticus. |
| Stems 2–12 in., usually slender and flaccid. Leaves 1–2 or wanting. Heads often proliferous; spikelets 2–15. Stamen 1. Style branches 3. Nut acutely trigonous, white | 6. S. inundatus. |
| Stems 8-16 in., rather stout, leafless. Spikelets 6–20, short, oblong. Stamen usually 1. Style-branches 2. Nut plano-convex, smooth and polished, pale | 7. S. sulcatus. |
| Stems 1–2 ft., rather stout, flaccid, leafless. Spikelets 10–30, long, linear. Stamens 3. Style-branches 3. Nut acutely trigonous | 8. S. prolifer. |
| Stems 1–3 ft., stout, rigid, erect, leafless. Spikelets numerous, short, ovoid, crowded. Stamens 3. Style-branches 3. Nut obtusely trigonous, brown | 9. S. nodosus. |
| Section II. Desmoschœnus. Tall, harsh, rigid and coriaceous. Spikelets numerous, spirally arranged around the upper part of the stem. Hypogynous bristles wanting. | |
| Rhizome long. Stems 1–3 ft. Leaves numerous, subsquarrose | 10. S. frondosus. |
| Section III. Eu-Scirpus. Usually large. Stem leafy at the base or leaves wanting. Spikelets usually panicled or umbelled, rarely in heads or solitary. Hypogynous bristles present. | |
| Stems acutely trigonous, 1–2 ft. high. Leaves 1–4, trigonous, shorter than the stem. Spikelets few, crowded into a small head | 11. S. americanus. |
