Leaves opposite; calyx usually tubular, 5-lobed; petals united at base, 4-12; stamens as many as petals; ovary superior.
Mountain Pink. Showy Centaury (Erythraea beyrichii) grows on gravelly limestone hills in Texas and Arkansas. The stems are branched near the base and often form hemispherical clumps a foot in diameter which are covered with pink flowers in June. The plants are being rapidly exterminated for ornamental purposes, for they are very showy and the flowers will last two weeks or more. The flowers have a united tubular corolla with 5 lobes.
The scientific name is from the Greek meaning “red.” The flowers of some species are red, but those in Texas are pink. The Texan centaury (Erythraea texense) is a very small plant with small flowers. It is found from Texas to Missouri in June and July. Buckley’s centaury or pink gentian (Erythraea calycosa) is found in moist soil in the western part of the state. It is a tall, slender plant 1-2 ft. high. It ranges from Missouri to Mexico. The centaury plants were formerly valued as a medicine for fever. They were gathered and dried at flowering time.
PURPLE GENTIAN. BLUEBELL
Purple Gentian. Bluebell (Eustoma russellianum) is also called Russell’s eustoma, Texas bluebell, blue gentian, blue marsh lily, and bosque blue gentian. The latter name is used in El Paso, where the purple gentian grows on the flood plain of the Rio Grande River. It is one of the loveliest flowers in the state, sometimes occurring in great profusion on moist prairies from Mexico to Colorado and Louisiana. It is especially abundant in Southeast Texas, where it is gathered in wholesale quantities by florists. It is an excellent cut-plant, the flowers lasting for several days and new buds continually opening.
Few people have had success in transplanting the purple gentian into their gardens. Only recently has there been a report of seeds successfully germinated. It is said that soaking for 48 hours in water will produce germination. Each flower produces a number of very minute seeds.
The large, bell-shaped flowers, 2-3 inches broad, are a bluish-purple; in fading, they spread widely and take on more of the blue tinge. They are constricted into a short narrow tube at the base. Inside, the flowers are marked with yellow at the base and have purple markings in the throat. The five stamens with large anthers are attached to the corolla tube. At the time the pollen is shed, the anthers lie in a horizontal position around the style. The stigmas are interesting. There are two diamond-shaped lobes which are erect until they are ready to receive pollen, and then they take a horizontal position. The calyx has five linear lobes which are united at the base with a colorless membrane. The oblong capsules are about half an inch long.
The plants are very smooth and are erect, with a few erect branches. The leaves are ovate-oblong and are usually 1-2½ inches long.
“Eustoma” means “open mouth”, referring to the large throat of the flower. The smaller bluebell in Southern Texas and Northern Mexico is Eustoma gracile.