Ischaemum byrone

HABIT Perennial. Stolons present. Culms geniculately ascending; 40–80 cm long. Culm-nodes bearded. Leaf-sheaths glabrous on surface. Leaf-sheath auricles erect; 3–4 mm long. Ligule an eciliate membrane; 1.5–3 mm long. Leaf-blades 7–20 cm long; 3–5 mm wide.

INFLORESCENCE Inflorescence composed of racemes; exserted, or embraced at base by subtending leaf.

Racemes 2; paired; 4–10 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes oblong; 3–4 mm long; flat and forming a U or V shape with the pedicel in rear view. Rhachis internode tip transverse; cupuliform.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels oblong; 3 mm long; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; lanceolate; laterally compressed; 5–6 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; without keels; 5 -veined; hirsute; dentate; 2 -fid; awned; both glumes awned; with 1–3 mm long awn. Companion sterile spikelet lemmas 4.5 mm long; dentate; 1-awned.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base truncate; inserted. Spikelet callus hairs 0.5 length of spikelet.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; coriaceous; 2-keeled; keeled above; keeled laterally. Lower glume surface flat; asperulous; hirsute. Lower glume hairs 4 mm long. Lower glume apex dentate; 2 -fid; muticous, or awned; 2 -awned. Lower glume awn 0.5–1 mm long. Upper glume lanceolate; coriaceous; 1-keeled; keeled above. Upper glume surface asperulous; rough above. Upper glume awned; 1 -awned. Upper glume awn 1–7 mm long.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 5 mm long; hyaline. Fertile lemma oblong; 5 mm long; membranous; without keel; 5 -veined. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 15–26 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1 length of lemma.

FLOWER Anthers 3; 2–2.5 mm long.

DISTRIBUTION Pacific: southwestern, south-central, and north-central.

NOTES Andropogoneae. Wagner 1993.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.