This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Bright blue, touched with white, fading to pale blue, about 1 in. long, borne on tall, erect, leafy spike. Calyx 5-parted, the lobes sharply cut, hairy. Corolla tubular, open to base on one side, 2-lipped, irregularly 5-lobed, the petals pronounced at maturity only. Stamens 5, united by their hairy anthers into a tube around the style; larger anthers smooth. Stem: 1 to 3 ft. high, stout, simple, leafy, slightly hairy. Leaves: Alternate, oblong, tapering, pointed, irregularly toothed, 2 to 6 in. long, 1/2 to 2 in. wide.
Preferred Habitat - Moist or wet soil; beside streams.
Flowering Season - July - October.
Distribution - Ontario and northern United States west to Dakota, south to Kansas and Georgia.
To the evolutionist, ever on the lookout for connecting links, the lobelias form an interesting group, because their corolla, slit down the upper side and somewhat flattened, shows the beginning of the tendency toward the strap or ray flowers that are nearly confined to the composites of much later development, of course, than tubular single blossoms. Next to massing their flowers in showy heads, as the composites do, the lobelias have the almost equally advantageous plan of crowding theirs along a stem so as to make a conspicuous advertisement to attract the passing bee and to offer him the special inducement of numerous feeding places close together.
The handsome Great Lobelia, constantly and invidiously compared with its gorgeous sister the cardinal flower, suffers unfairly. When asked what his favorite color was, Eugene Field replied: " Why, I like any color at all so long as it's red!" Most men, at least, agree with him, and certainly humming-birds do; our scarcity of red flowers being due, we must believe, to the scarcity of humming-birds, which chiefly fertilize them. But how bees love the blue blossoms!
There are many cases where the pistil of a flower necessarily comes in contact with its own pollen, yet fertilization does not take place, however improbable this may appear. Most orchids, for example, are not susceptible to their own pollen. It would seem as if our lobelia, in elevating its stigma through the ring formed by the united anthers, must come in contact with some of the pollen they have previously discharged from their tips, not only on the bumblebee that shakes it out of them when he jars the flower, but also within the tube. But when the anthers are mature, the two lobes of the still immature stigma are pressed together, and cannot be fertilized. Nevertheless, the hairy tips of some of the anthers brush off the pollen grains that may have lodged on the stigma as it passes through the ring in its ascent, thus making surety doubly sure. Only after the stigma projects beyond the ring of anthers does it expand its lobes, which are now ready to receive pollen brought from another later flower by the incoming bumblebee to which it is adapted.
Linnaeus named this group of plants for Matthias de l'Obel, a Flemish botanist, or herbalist more likely, who became physician to James I. of England.
Preferably in dry, sandy soil or in meadows, and over a wide range, the slender, straight shoots of Pale Spiked Lobelia (L. spi-cata) bloom early and throughout the summer months, the inflorescence itself sometimes reaching a height of two feet. At the base of the plant there is usually a tuft of broadly oblong leaves; those higher up narrow first into spoon-shaped, then into pointed, bracts, along the thick and gradually lengthened spike of scattered bloom. The flowers are often pale enough to be called white. Like their relatives, they first ripen their anthers to prevent self-fertilization.
The lithe, graceful little Brook Lobelia (L. Kalmii), whose light-blue flowers, at the end of thread-like footstems, form a loose raceme, sways with a company of its fellows among the grass on wet banks, beside meadow runnels and brooks, particularly in limestone soil, from Nova Scotia to the Northwest Territory and southward to New Jersey. It bears an insignificant capsule, not inflated like the Indian tobacco's; and long, narrow, spoon-shaped leaves. Twenty inches is the greatest height this little plant may hope to attain.
Great Lobelia Or Blue Cardinal Flower. (Lobelia syphilitica.)
Not only beside water, and in it, but often totally immersed, grows the Water Lobelia or Gladiole (L. Dortmanna). The slender, hollow, smooth stem rises from a submerged tuft of round, hollow, fleshy leaves longitudinally divided by a partition, and bears at the top a scattered array of pale-blue flowers from August to September.