Amphicarpum

HABIT Annual (1), or perennial (1). Rhizomes absent (1), or elongated (1). Culms erect, or geniculately ascending (1); 10–47.5–80 cm long; rooting from lower nodes (1/1). Lateral branches sparse (1/1). Ligule a fringe of hairs. Leaf-blades linear (1), or lanceolate; herbaceous, or coriaceous (1). Leaf-blade margins cartilaginous (1/1).

INFLORESCENCE Inflorescence a panicle, or composed of racemes (1).

Panicle open.

Racemes single (1/1), or borne along a central axis (1/1).

Spikelets appressed (1/1), or ascending (1/1); solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 6–7–8 mm long; falling entire.

GLUMES Glumes one the lower absent or obscure (1), or two (1); shorter than spikelet, or reaching apex of florets (1); thinner than fertile lemma. Lower glume ovate (1/1); membranous (1/1), or scarious (1/1); without keels (1/1); 1 -veined (1/1). Lower glume lateral veins absent (1/1). Lower glume surface without pits (1/1). Lower glume apex obtuse (1/1). Upper glume lanceolate; 0.9–0.925–1 length of adjacent fertile lemma; membranous; without keels; 5 -veined (1), or 7 -veined (1). Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; membranous; 5 -veined; acute. Fertile lemma elliptic (1), or oblong (1); coriaceous (1), or indurate; of similar consistency on margins (1), or much thinner on margins (1); without keel; wingless; 5 -veined. Lemma surface unwrinkled; without grooves. Lemma margins flat (1), or involute (1). Lemma apex apiculate. Palea 1 length of lemma; indurate; 2 -veined (1/1).

FLOWER Lodicules 2 (1/1); fleshy (1/1). Anthers 3. Stigmas 2 (1/1). Ovary glabrous (1/1).

CLEISTOGENES AND VIVIPARY Cleistogenes present; underground.

DISTRIBUTION North America.

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