Lobelia spicata var. spicata

Native

Dry. Prairies, forest openings, savannas, streambanks, meadows, pastures. Full or partial sun.

June to July

Pale blue or white

8″ to 40″

This is a, erect, perennial forb that rises on a single stem from a taproot and fibrous roots. It can be 8″ to 40″ tall, but usually reaches no more than 32″ in height at maturity.

The stems are erect or ascending, green, and usually unbranched. They are 4- or 5-angled, especially near the top, with narrow wings along the ridges. They are often sparsely to moderately covered with short, curved to spreading hairs near the base, becoming hairless or almost hairless near the top.

The leaves are alternate, ascending, and stalkless. The leaf blades are ⅜″ to 2¾″ long, and ⅜″ to 1″ wide. They are egg-shaped to egg lance-shaped, lance-shaped, or narrowly oblong. They are rounded at the tip or angled to a blunt point. The leaves toward the base are broad, becoming narrower and shorter as they ascend the stem. The base of the leaf blade is narrowed and continues down along the stalk as a pair of wings. The margins are usually untoothed and have a fringe of short, fine, spreading hairs. The upper and lower surfaces are hairless or sparsely covered with straight, stiff, sharp, appressed hairs. Basal leaves, if present, are no larger than lower stem leaves.

The inflorescence is a loosely- or densely-flowered, spike-like, unbranched, 4″ to 12″ long cluster (raceme) at the end of the stem. The inflorescence axis is hairless or sparsely hairy. There is a 1½″ to 6″ long section of bare axis between the lowermost flower and the uppermost leaf.

Each flower is borne on a ⅛″ to ⅜″ long stalk (pedicel) rising from the axil of a hairless bract. The lower bracts are leaf-like, lance-shaped, and up to 3 ⁄5″ long, becoming much shorter and linear as they ascend the stem. There is also a pair of minute bracts closely subtending each calyx. The flowers are borne upside down due to the twisting of the pedicel.

Each flower is ¼″ to ⅜″ long. At the base there are 5 green sepals (calyx) that are fused at their base into a 1 ⁄32″ to 1 ⁄16″ long tube, then separated into five ⅛″ to ¼″ long lobes. The calyx tube is finely hairy or has tiny, nipple-like projections (papillae) between the ribs. The calyx lobes may or may not have ear-like projections (auricles) at the base. If auricles are present, they are minute, no more than 1 ⁄64″ long. The calyx tube does not become inflated as the fruit matures.

There are 5 pale blue or white petals fused at their base into a ⅛″ to 3 ⁄16″ long corolla tube, then separated into an upper and lower lip. The corolla tube does not have longitudinal slits. The “upper” lip (appearing lower due to the twisting of the pedicel) is large and is split into three lobes up to 3 ⁄16″ long and 1 ⁄16″ wide. The “lower” lip (appearing upper) is split nearly to the base into 2 much narrower lobes. The lobes of the “lower” lip are spreading, upward-curved, and up to ⅛″ long, with a tuft of white hairs near the base. There are 5 stamens with blue anthers. The filaments are fused from just above the base into a tube surrounding the style. The anthers are fused into a ring around the style. The lower 2 anthers are shorter than the others and have white tufts of hair at the tip. The style and filament tube protrude from between the 2 lobes of the “lower” lip and bends downward near the tip. The flowers are not fragrant.

The fruit is a two-chambered, hemispherical capsule with numerous seeds.

Brook lobelia (Lobelia kalmii) is a much smaller plant, no more than 16″ tall at maturity. The leaves are held erect. Lower leaves are narrower, upper leaves are linear.

Palespike lobelia (Lobelia spicata var. hirtella) stem, bracts, calyx, and leaves below the midpoint of the stem all have stiff, spreading hairs.

Palespike lobelia (Lobelia spicata var. spicata f. campanulata) has white anthers. It occurs sporadically within populations of plants with blue anthers.

Sources: 4, 7.