Ptilimnium nuttallii (DC.) Britt.

Family - Apiaceae

Stems - To 60cm tall, from weak roots, erect, herbaceous, glabrous, rounded to slightly 4-angled, simple or with few branches.

Leaves - Alternate, petiolate, pinnately divided, glabrous, to 5cm long. Petioles to 4-5mm long, sheathing and flattened. Leaflets opposite, lowest pair often divided again (bifurcate), all leaflets filiform.

Inflorescence - Terminal compound umbels. Primary rays of umbels typically 8-11, to 9mm long in flower, longer in fruit, glabrous, subtended by 3-15 unequal threadlike bracts (to +1cm long), glabrous. Umbellets of typically 5-11 flowers. Raylets to 3mm long in flower, longer in fruit, glabrous, subtended by few short threadlike bracts.

Bracts of rays.

Flowers - Petals 5, white, equal, to +/-1.3mm long, 1mm broad, glabrous, apiculate to caudate and incurved at apex. Stamens 5, alternating with petals. Filaments white, .8mm long, glabrous. Anthers pinkish-rose, +/-.3mm long. Styles 2, short, with broad expanded stylopodium. Ovary inferior, 2-locular, with one ovule per locule. Sepals 5, alternating with petals, whitish, triangular-attenuate, .3mm long. Fruits 2.4mm broad, glabrous, ovoid to orbicular, with persistent sepals and styles.

Fruits.

Flowering - June - August.

Habitat - Moist to wet prairies, swampy meadows, wet depressions of glades, wet ground along railroads.

Origin - Native to U.S.

Other info. - This species is small but easy to ID in the field because of its very fine leaves, weak stems, and large umbels of flowers. It grows in moist locations which is another major factor used in identification. The plant can be found in large numbers in some areas, such as prairies.

Photographs taken at the Dorris Creek Prairie Conservation Area, Barton County, MO., 7-28-00, and at Bethel Prairie, Barton County, MO., 7-4-03.