GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Amphicarpum muhlenbergianum

HABIT Perennial. Cataphylls evident. Rhizomes elongated. Culms erect, or geniculately ascending; 10–70 cm long; rooting from lower nodes. Lateral branches sparse. Leaves cauline. Leaf-sheaths ribbed; hispid. Ligule a fringe of hairs. Leaf-blade base simple, or broadly rounded. Leaf-blades lanceolate; (0.5–)3–10 cm long; 5–10 mm wide; herbaceous to coriaceous. Leaf-blade surface smooth, or scaberulous; glabrous. Leaf-blade margins cartilaginous.

INFLORESCENCE Inflorescence a panicle, or composed of racemes.

Panicle open; lanceolate; 10–25 cm long; contracted about primary branches. Primary panicle branches distant; 1 -nate; indistinct the panicle almost racemose, or simple; 1.5–15 cm long. Panicle branches scaberulous.

Racemes 1–4; single, or borne along a central axis; 1.5–15 cm long. Central inflorescence axis 5–10 cm long.

Spikelets ascending, or appressed; solitary. Fertile spikelets pedicelled. Pedicels filiform; 1–8 mm long; scabrous.

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

GLUMES Glumes dissimilar; reaching apex of florets, or shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1 mm long; 0.1–0.2 length of spikelet; membranous, or scarious; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse. Upper glume lanceolate; 0.9–1 length of adjacent fertile lemma; membranous; without keels; 5 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 length of spikelet; membranous; without keels; 5 -veined; acute. Fertile lemma elliptic; 5.5–6 mm long; coriaceous, or indurate; without keel; 5 -veined. Lemma lateral veins transversely connected at apex. Lemma margins involute. Lemma apex apiculate. Palea elliptic; 1 length of lemma; indurate; 2 -veined. Palea surface papillose. Palea apex acuminate.

FLOWER Lodicules 2; cuneate; 0.5 mm long; fleshy. Anthers 3; 4 mm long. Stigmas 2. Ovary glabrous.

CLEISTOGENES AND VIVIPARY Cleistogenes present; underground.

DISTRIBUTION North America: southeast USA.

NOTES Paniceae. TB.

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