多年生草木，高者有一米左右。莖直立，多分枝，枝皆腋生，莖兩側各有緃棱一條。單葉對生，長橢圓形或披針形，長一到三釐米，基部無柄，有時抱莖，散佈透明腺點，葉緣有黑色腺點。聚傘花序頂生。花較大，黃色，萼片五。花瓣五。雄蕊多數，組成三束，花瓣邊緣同花藥，均有黑色腺點，子房上位，一室，花柱三裂。蒴果長圓形，具泡狀小突起，開裂。種子圓筒形。花期六到七月，果期九到十月。
Perennial grass and trees, about one meter tall. The stems are erect, multi-branched, and the branches are axillary, and there is a ridge on each side of the stem. Leaves palliate opposite, oblong or lanceolate, one to three centimeters long, sessile at base, sometimes holding stems, scattered with transparent glandular points, with black glandular points on the leaf margins. The inflorescence of the umbrella is apical. The flowers are larger, yellow, sepals five. Petal Five. The stamens are mostly composed of three bunches, the petal margins and anthers, all with black glandular spots, the ovary is superior, one chamber, and the columella is trilobed. The capsule is oblong, with small vesicular protrusions, dehisced. The seeds are cylindrical. The flowering period is from June to July, and the fruiting period is from September to October.