[C. a. var. laysanensis F. Brown; C. calyculatus Cav. var. uniflorus Hillebr.; C. laysanensis (F. Brown) St. John; C. pedunculatus Degener & Whitney]
(end [1 var. Ex]) Kamanomano, ku- manomano
Perennials; culms robust, 30-200 cm tall, swollen at nodes, internodes short, scabrous below panicle. Sheaths compressed-keeled, much longer than internodes, glabrous; ligule membranous, fimbriate, 1-1.2 mm long; blades flat or folded, 20-40 cm long, 5-25 mm wide, upper surface scabrous, lower surface glabrous, midrib prominent. Inflorescence composed of racemes 5-10 cm long, the axis densely puberulent; burs cylindrical to lanceoloid, somewhat reflexed at maturity, fusiform, 8-18 mm long, bur receptacle narrow in lower part, expanding above, 3-4 mm long, densely pubescent, outer series of bristles numerous, somewhat spreading, 2-3 mm long, retrorsely scabrous, the larger ones tomen- tulose at base, body of bur cleft V3-V2 its length, lobes erect, appressed, forming an irregular beak, densely tomentose near middle, apex retrorsely scabrous; spikelets 1 per bur; glumes unequal, scaberulous, first glume 2-3 mm long, 5-7-nerved, awn- tipped; sterile lemma 5-6 mm long, scaberulous, 5-7-nerved, awn-tipped; sterile palea indistinctly 3-nerved, slightly shorter than lemma, scaberulous on margins and keel near apex; fertile lemma 5-6 mm long, indistinctly 5-nerved, apex acute; fertile palea 4-5 mm long, membranous, scaberu-lous at base, apex acute. Caryopsis ovoid, ca. 2.6 mm long, ca. 1 mm in diameter. Occurring on sand and on dry, rocky slopes and ridges in partial shade, 0-760 m, on Kure and Midway atolls, Laysan, 0‘ahu, Lana‘i, and Maui.—Plate 222.
Two varieties are recognized: var. agri-monioides [incl. Cenchrus calyculatus var. uniflorus, C. pedunculatus], with burs 10-15 mm long, culms 30-70 cm tall, and leaves 5-15 mm wide (occurring on dry, rocky slopes and ridges, 580-760 m, on 0‘ahu, Lana‘i, and Maui); and var. lay- sanensis, distinguished by burs 8-18 mm long, robust culms 50-200 cm tall, and leaves 15-25 mm wide (growing in sand, 0-10 m, on Kure Atoll, Midway Atoll, and Laysan). Variety laysanensis is probably extinct; it was last collected on Kure Atoll in 1961 (Lamoureux 1912, BISH). Cenchrus pedunculatus, described on the basis of pubescence, falls within the range of variation in C. agrimonioides and therefore is not considered unique.
According to Hillebrand (1888), this species is most closely allied to species of the south Pacific.