On the dry uplands, on those rolling, gravelly hills where poverty grass denotes a kindred poverty of the soil, the rare little bluets blossom in April. Although other bluets (Houstonia coerulea) sometimes are found in northern Illinois and even more commonly northward and eastward, this is the little southwestern species which, further south in Missouri, covers sunny hills and pastures with millions of tiny bright flowers. They are so abundant that the ground is blue with beds of minute and beautiful blossoms.
Houstonia minima Beck.
Early spring Open bills.
We have two very similar Houstonias, very small, both with deep purple flowers, both called "star-violets", and both are winter annuals. They are Houstonia minima and Houstonia pusilla. The former has the longer calyx and grows on very dry ground. The Museum has collections from several counties, mostly in the south and as far north as Rock Island. The long-leaved houstonia (Houstonia longifolia) often reaches a foot in height, has a many-branched, wiry stem, and small white flowers with pointed, oval petals, and a tube which is longer than the petals. It is found commonly in rocky or gravelly woods in late spring, and often continues to bloom throughout the summer.
Bluets are among the most delicate and charming of the spring flowers in any part of the country. The plant is only one to three inches tall with tiny, bright green, oval leaves placed opposite each other on the thready, weak stems. One flower grows at the tip of each stem; sometimes the stalk forks near the base, but usually it is straight, simple, and one-flowered. The exquisite blossom, a quarter-inch wide, is four-parted and tubular, the tube in this species no longer than the four spreading petals. The flower is bright blue-lavender, clear blue, purple, white, or pale pink, the center marked with lour purple-rose dots.