Juncus balticus

A flowering stem has no leaves to speak of, just one or more bladeless sheaths at the base. Sheaths are reddish at the base and green to brown above. Stems are dark green, round in cross-section, smooth, erect, unbranched, and create colonies from long rhizomes. Flowers are single, not in heads of 2 or more, on stalks of varying lengths, with 6 tepals (petals and similar sepals) in 2 layers, 3.5 to 5.5 mm long. In North America, experts generally recognize three main forms of Baltic rush which differ in flower proportions and in the leafiness of the stems. Besides differing in floral features, rushes also can be distinguished from grasses and sedges by their solid, round stems. By comparison, sedges have 3-sided stems, and grasses have hollow, round stems. The rhyme “sedges have edges, rushes are round, and grasses are hollow right up from the ground” has helped countless plant taxonomy students remember these differences at exam time.