Eragrostis cilianensis (All.) Vignolo ex Janch.

Stink Grass

© DETenaglia

Family - Poaceae/Eragrostideae

Habit - Annual grass with fibrous roots, forming tufts.

Stems - To 40cm long, spreading to ascending, herbaceous, multiple from the base, glabrous but often with a small ring of glandular bumps below the nodes. Plants annual.

Leaves - Blades to 20cm long, to 7mm broad, flat, glabrous. Leaf margins with many minute glands which can be felt or seen with a lens. Leaf bases with ciliate hairs. Sheaths glabrous but with glands on the margins, ciliate on the margins near the apex. Ligule a line of minute hairs to 1mm long.

	Leaf base.
© DETenaglia

	Ligule.
© DETenaglia

	Leaf blade margin with arrow showing gland.
© DETenaglia

Inflorescence - Paniculate arrangement of spikelets, fairly dense, to 15cm long, ovate in outline, with a slightly silvery-greyish cast. Branches of the inflorescence ascending to spreading, glabrous or with floccose axillary hairs, also with glands as the leaves.

	Inflorescence.
© DETenaglia

	Inflorescence branch.
© SRTurner

Flowers - Spikelets to 15mm long, 2-4mm broad, oblong-lanceolate in outline, with typically 10-20 florets. Glumes of the florets to 2.3mm long, the upper slightly longer than the lower, both glumes typically glabrous but usually with glands. Lemmas to 2.8mm long, acute to acuminate at the apex, keeled, with glands along the midvein.

	Spikelets.
© DETenaglia

	Spikelets.
© SRTurner

Flowering - June - October.

Habitat - Streambanks, glades, fields, pastures, disturbed sites, roadsides, railroads.

Origin - Native to Europe.

Lookalikes - Other species of Eragrostis.

Other info. - This weedy species is found throughout most of Missouri and across the continental U.S. The plant can be identified by its tufts of hairs at the base of the leaves and the small, warty glands which are present on leaf margins and stem nodes. There are numerous lookalikes, and details such as leaf width and spikelet size can be important. Distinguishing species in this genus can be challenging.

The glands on the foliage sometimes emit a foul odor when crushed, leading to the common name "Stink Grass." It is believed to be mildly toxic if ingested. Ingestion of large quantities can poison horses. Fortunately, the smell of the plant usually discourages grazing.

Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 7-23-03 (DETenaglia); also along the Katy Trail near Dutzow, Warren County, MO, 8-16-2020 (SRTurner).