Bellflower family (Campanulaceae)
Description: This perennial plant is ¾–2¼' tall and unbranched. It tends to be short-lived. The central stem is often ridged or angular near the inflorescence. The sessile alternate leaves occur primarily along the lower half of the stem, and are up to 3½" long and 1" across. They are usually lanceolate or narrowly ovate, but are sometimes wider at the tip than the base. Their margins often have widely spaced teeth, but are sometimes smooth. The inflorescence consists of a long spike of flowers about 3-12" in length. The flowers are light blue or white, and about 1/3" (8 mm.) across. Each flower has a smaller upper lip that is divided into 2 lobes, and a larger lower lip that is divided into 3 lobes. There is a purple or dark blue stigma that is strongly exerted from the upper part of the corolla tube, and bends downward at its tip. The base of the flower consists of a tubular calyx with 5 teeth. Sometimes tiny appendages (0-4 mm. in length) occur between the teeth of the calyx. The blooming period occurs during mid-summer and lasts about a month. There is no noticeable floral scent. Later in the year, the flowers are replaced by seedpods. The latter split open at the top, exposing numerous tiny seeds that are easily carried by occasional gusts of wind. The root system consists of a central taproot.
Cultivation: The preference is full or partial sun and moist to slightly dry conditions. Growth is best when the soil is rich and loamy, but it can also be somewhat rocky. Some of the lower leaves may turn yellow and fall off the stem during a drought. There is also a tendency for this plant to flop over if it is spoiled with too much water or fertilizer and lacks adequate support from adajacent plants. It is necessary to keep the soil consistently moist in order to keep the small seedlings alive.
Range & Habitat: The native Pale-Spiked Lobelia occurs occasionally in the majority of counties in Illinois, but it is less common or absent in the SE portion of the state (see Distribution Map). Habitats include moist to mesic black soil prairies, typical savannas and sandy savannas, moist meadows in woodlands or near rivers, thickets, bluffs, limestone glades, and abandoned fields. This is usually an understory plant whose inflorescence appears among the taller grasses and forbs.
Faunal Associations: The flowers attract long-tongued bees primarily, including little carpenter bees (Ceratina spp.), miner bees (Melissodes spp.), mason bees (Osmia spp.), and leaf-cutting bees (Megachile spp.). Small butterflies and skippers also visit the flowers occasionally, which are probably less effective at pollination. All of these insects seek nectar. The leaves and stems contain a watery white latex that is toxic, therefore most mammalian herbivores are less likely to eat this plant than others. However, deer appear to be somewhat immune to the effects of the toxins in the foliage. The seeds are too small to be of any interest to birds.
Photographic Location: The photographs were taken at Loda Cemetery Prairie in Iroquois County, Illinois.
Comments: With its smaller pale flowers, Pale-Spiked Lobelia is less showy than some of its better known relatives, such as Lobelia cardinalis (Cardinal Flower) and Lobelia siphilitica (Great Blue Lobelia), but it has better resistance to dry conditions after becoming established. The flowers of these species all share a similar structure, but vary considerably in their size and color. Another species in this genus with small flowers, Lobelia kalmii (Kalm's Lobelia), has more narrow leaves than Pale-Spiked Lobelia. Across different populations of Pale-Spike Lobelia, there is some variability in the color of the flowers, hairiness of the foliage, and the length of the tiny appendages between the calyx teeth.