Orcuttia

Plants annual; viscid-aromatic, pilose, sometimes sparsely so, producing long, juvenile, floating basal leaves. Culms 3-35 cm, erect, ascending, or decumbent, sometimes becoming prostrate, not breaking apart at the nodes, usually branching only at the lower nodes. Leaves without ligules, sometimes with a "collar" line visible at the junction of the sheath and blade, especially when dry; blades flat or becoming involute in drying. Inflorescences terminal, clavate to capitate spikes, exserted at maturity, spikelets distichously arranged; disarticulation tardy, above the glumes and between the florets. Spikelets laterally compressed, with 4-40 florets. Glumes irregularly 2-5-toothed; lemmas deeply cleft and strongly 5-veined, veins terminating in prominent mucronate or awn-tipped teeth 1/3 - 1/2 or more as long as the lemma bodies, each tooth with an additional weaker vein on either side of a strong central vein, these extending about halfway to the base of the lemma; paleas well-developed, 2-veined; lodicules absent; anthers 3, white or pinkish, exserted on long, slender, ribbonlike filaments at anthesis; styles 2, apical, elongate, filiform, stigmatic for 1/3 – 1/2 of their length; stigmatic hairs short, often sparse. Caryopses slightly compressed laterally, oblong to elliptic; embryos 3/4 as long as to equaling the caryopses; epiblast absent, x = 10, probably.

Distribution

Calif.

Discussion

Orcuttia is a genus of five species, all of which are restricted to vernal pools and similar habitats in California and northern Baja California, Mexico.

Selected References

None.

Lower Taxa

Orcuttia californica, Orcuttia inaequalis, Orcuttia pilosa, Orcuttia tenuis, Orcuttia viscida

Key

1	Lemma teeth unequal, the central tooth the longest.	> 2
2	Lemmas 6-7 mm long, the teeth terminating in awns at least 1 mm long; caryopses 2.3-2.5 mm long	Orcuttia viscida
2	Lemmas 4-5 mm long, the teeth sharp-pointed or with awns to 0.5 mm long; caryopses 1.3-1.8 mm long.	> 3
3	Plants sparingly hairy; culms usually prostrate; spikes clavate	Orcuttia californica
3	Plants conspicuously hairy, grayish; culms erect or decumbent; spikes somewhat capitate	Orcuttia inaequalis
1	Lemma teeth essentially equal in length.	> 4
4	Culms usually prostrate; caryopses 1.5-1.8 mm long	Orcuttia californica
4	Culms erect, ascending, or decumbent; caryopses 2-3 mm long.	> 5
5	Culms 1-2 mm thick, branching only at the lower nodes; spikes congested, crowded towards the top; leaf blades 3-5 mm wide	Orcuttia pilosa
5	Culms 0.5-1 mm thick, often branching from the upper nodes; spikes not congested, even towards the top; leaf blades 1.5-2 mm wide	Orcuttia tenuis