Monographs Details: Phlebotaenia cowellii Britton
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - This endemic tree, now rare, is noteworthy for its beauty when in bloom, its valuable, hard, yellowish-white wood, and its botanical relationships. It may be said to be characteristic of the dry southern parts of Porto Rico, widely scattered trees existing, in 1931, from the water-gap of the Jueyes River, north of Salinas, westward to La Parguera, south of San German, and it has been reported to us as formerly much more abundant in that area; it is not wholly restricted to this distribution, for trees exist, or have existed, on the limestone hills of northern Porto Rico, as shown by conserved herbarium specimens. Trees bloom, in different years, from February to late April, covering the usually leafless twigs, for the leaves mostly fall soon before the flowers appear, with enormous numbers of small purple flowers, conspicuous in the landscape, making it one of the most elegant of all trees. The Spanish names Carocolillo and Palo de tortuga are sometimes applied to it. Its rarity is partly explained by the poor germination of the seeds; repeated search near and under trees has failed to detect a seedling, while the ground is often littered by the fallen fruits; attempts to germinate seed in gardens have met with indifferent success. The species was first botanically described from specimens obtained from a tree first observed by Mrs. Britton, near Coamo Springs, in 1906.
Phlebotaenia (Greek, referring to the characteristic veining of the leaves) is a genus established by Grisebach, a profound student of West Indian Floras, in 1860, based on a Cuban tree, the only other species yet known to botanists. These trees have rather thick, broad, stalked leaves, with many lateral, nearly parallel and straight primary veins, and clustered, purple, quite irregular flowers. The calyx is composed of 5, unequal sepals, the 2, lateral, interior ones (wings) larger than the others; there are 3, partly united, petals (keel), and sometimes 2 smaller ones; the 8 stamens are united by their filaments into a split sheath; the ovary is 2-celled, with only 1 ovule in each cavity, the style simple, the stigma small. The fruit is a flattened capsule, broadly 2-winged on one side and narrowly 2-winged on the other.
Phlebotaenia Cowellii (commemorates John Francis Cowell, 1852-1915, Director of the botanical garden of Buffalo, diligent student of West Indian plants, who aided in collecting the first flowers of the tree known to botanists), attains a maximum height of about 20 meters, with a trunk up to about 0.7 meter in diameter, with smooth, gray bark. The broad, mostly elliptic or ovate leaves are smooth, pointed, from 5 to 12.5 centimeters long; the clusters of short-stalked flowers are short and numerous; the smaller sepals are elliptic, rounded, from 2 to 4.5 millimeters long, the wings about 15 millimeters long, the 3-lobed keel about as long. The flat, oblique fruit, including its membranous wings, is 2 to 3 centimeters long.
Our illustration was first published in "Addisonia", plate 280, December, 1923.
Phlebotaenia Cowellii Britton, Torreya 7: 38. 1907.
Phlebotaenia portoricensis Urban, Symbolae Antillanae 5: 382. 1908.
Polygala Cowellii Blake, Contributions from the Gray Herbarium 47:10. 1916.