Hordeum arizonicum

HABIT Annual. Culms 20–60 cm long. Leaf-sheaths pubescent. Leaf-sheath oral hairs lacking. Leaf-sheath auricles falcate. Ligule an eciliate membrane. Leaf-blades 3–5 mm wide. Leaf-blade surface pubescent; sparsely hairy.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; bilateral; 3–12 cm long. Rhachis fragile at the nodes; flattened. Spikelet packing broadside to rhachis. Rhachis internodes oblong; falling with spikelet above.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels oblong.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; lanceolate; dorsally compressed; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes subulate. Companion sterile spikelet lemmas 1; exserted from glumes; 1-awned.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 8–9 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes collateral; similar; exceeding apex of florets; gaping. Lower glume subulate; 15–20 mm long; 1 length of upper glume. Upper glume subulate; 15–20 mm long.

FLORETS Fertile lemma lanceolate; 8–9 mm long; coriaceous; without keel; 5 -veined. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 15–22 mm long overall.

FLOWER Anthers 3. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; hairy at apex. Hilum linear.

DISTRIBUTION North America: southwest USA and Mexico.

NOTES Triticeae. Gr Baja Cal 1994.

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