Stems 3-5 dm. Leaves widely spaced proximally, becoming clustered to whorled near inflorescence; blade 1-8 cm. Inflorescences with inflated rachises (rays) and peduncle. Flowers: calyx 3-10 mm, longer than corolla; corolla white, 3-6 mm. Capsules 1.5-3 mm. Seeds 0.4-0.6 mm. 2n = 22.