Trillium nivale Riddell - Snow Trillium

Trillium nivale plant

Family - Liliaceae

Stems - From a rhizome and thickened roots, to -15cm tall, erect, single from the base, simple, herbaceous, glabrous, reddish, somewhat 5-angled.

Trillium nivale rhizomeRhizome.

Leaves - 3, whorled, petiolate. Petioles 3-4mm long, mostly glabrous but minutely translucent papillate on the margins (use a lens to see). Blades ovate, to +3cm long, +1.5cm broad, shiny silvery-green below, pale bluish-green above, glabrous above, translucent papillate below, acute to subacute at the apex, entire, with papillae on the margins (use a lens to see papillae), with 5 main veins. Lateral veins reticulate. Veins impressed above, expressed below.

Trillium nivale leaves

Inflorescence - Single flower terminating the stem. Peduncle to +1.5cm long, glabrous, purplish. Flowers nodding slightly or erect.

Flowers - Petals 3, white, glabrous, to 3cm long, +1cm broad, oblong to elliptic, entire, blunt to slightly emarginate at the apex, tapering to the base, distinct. Stamens 6, alternating smaller and larger, erect, distinct. Filaments to 5mm long, -1mm broad, white, slightly compressed. Anthers yellow, to +6mm long, -2mm broad, longitudinally dehiscing. Anther connective greenish. Styles 3, erect. curled at the apex, to 1cm long, white at the apex, yellow to greenish basally, distinct. Ovary sessile, yellowish, superior, glabrous, 3-lobed, 3mm long and broad, 3-locular, with many ovules. Placentation axile. Sepals 3, green, slightly spreading, +/-2cm long, 5-6mm broad, lanceolate, blunt to slightly emarginate at the apex, with 5 parallel veins, with a scarious margin .1mm thick, glabrous.

Trillium nivale sepalsSepals.

Trillium nivale flowerFlower close-up.

Flowering - March - April.

Habitat - Mesic upland forests on steep, open, north-facing slopes above streams and rivers - on limestone and chert substrates.

Origin - Native to U.S.

Other info. - This small species is the smallest Trillium in Missouri and the first to bloom each spring. The plant is uncommon in the state and can only be found in a handful of counties. Its very selective habitat limits its range in Missouri.
T. nivale is an easy species to identify in the field (if you're lucky enough to find it) because of its small size, habitat, and white flowers. Plants are usually found in large numbers in a given area.

Photographs taken in Lincoln County, MO., 3-19-04.


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