white turtlehead

not listed

N5 - Secure

SNR - Unranked

not listed

OBL - Obligate wetland

OBL - Obligate wetland

OBL - Obligate wetland

White turtlehead is a 20″ to 32″ tall, erect, perennial forb that rises on a single stem from a taproot and rhizomes. It sometimes forms colonies.

The stems are erect and hairless. They are square but have rounded angles, sometimes causing the stem to appear round. They are usually unbranched, sometimes sparingly branched above the middle.

The leaves are opposite and short stalked or stalkless. Each pair of opposite leaves is rotated 90 degrees from the pair below. The leaf blade is unlobed, linear to lance egg-shaped, up to 6″ long, and ⅜″ to 1¼″ wide. They taper to a sharp point at the tip. The upper and lower surfaces are hairless. The margins are finely toothed with sharp, outward- or forward-pointing teeth.

The inflorescence is a dense, 1¼″ to 3″ long spike of flowers at the end of the stem. The spike is subtended by a pair of slightly smaller leaves. Each flower is subtended by a few modified leaves (bracts) that resemble the sepals.

The flowers are 1″ to 1⅜″ long. There are 5 sepals, 5 petals, 4 fertile stamens, 1 infertile stamen (staminode), and 1 style. The sepals are green. They are fused at the base then deeply separated into 5 broadly elliptic lobes. The petals are white, sometimes partly greenish-yellow, sometimes tinged with pink or purple toward the tip. They are fused at the base into a long tube with a shallowly 2-lobed upper lip and a shortly 3-lobed lower lip. The tube is much longer than the lobes. The upper lip arches downward. It is said to resembe the head of a turtle, giving this plant its common name. The middle lobe of the lower lip is elevated and partially or almost completely encloses the throat. The upper surface is covered with long, soft, shaggy, white hairs. The fertile stamens have flat, hairy filaments and densely hairy anthers. The sterile staminode is green and is much shorter and narrower than the stamens. The flowers are not fragrant.

The fruit is an egg-shaped seed capsule with numerous seeds.

20″ to 32″

White

Wet. Streambanks, wet meadows, open wet woodlands, sedge meadows, marshes. Full sun to partial shade.

July to September

White turtlehead is the primary, but not only, plant on which the Baltimore checkerspot lays its eggs.

Sources

2, 3, 4, 5, 7, 30

Native

Uncommon

Plant

Inflorescence

Flower

Location: St. Louis Co. MN