| Monocotyledon | Literature for Cyperus involucratus
Smith, 1979; Wagner et al., 1990, 1999; Lorence & Wagner, 2019. |
| Cyperaceae -- The Sedge Family | Bibliography |
| Cyperus involucratus | |
Common name(s): umbrella sedge, `ahu`awa haole, pu`uka`a haole |
| General Information | ||
|---|---|---|
| Distribution | Native of tropical Africa and Arabia.In the Hawaiian Islands, naturalized on Midway, Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i. | |
| Habit |
Perennial herb with short, woody
rhizomes; culms densely tufted, 50‒150
cm tall, obtusely trigonous to subterete in proximal part, scabrous below the
corymb. |
|
| Leaves |
Leaves reduced to bladeless sheaths; basal sheaths pale green, 10‒20
cm long, obliquely truncate at the orifice, proximal ones yellowish brown, forming a cataphyll. |
|
| Flowers |
Inflorescences large, dense,
decompound, corymbose, 15‒30 cm in
diameter, primary rays numerous, slender, 7‒10 cm long, each bearing 4‒10 secondary rays 1‒1.5 cm long; involucral bracts numerous, stiff, flat, subequal, ca. twice as long as the corymb, 2‒12 mm wide, apex abruptly acute. Spikelets clustered at apices of secondary rays, densely
6‒30-flowered, lanceolate oblong to elliptic, flattened, 3‒9 mm long, 1.7‒3 mm wide, rachilla not winged; glumes pale green and variegated with rusty brown, membranous, ovate, 1.5‒2 mm long, 3-or 5-veined, keel prominent, apex acute; stamens 3, anthers linear, ca. 1 mm; style nearly as long as the achene, stigmas 3, elongated. |
|
| Fruit |
Achenes brown, obovoid-ellipsoid, trigonous, ⅓‒¼ as long as the glume. |
|
| Chromosomes |
2n = 30, 32 |
|
| Contributor |
David Lorence |
