Plasteurhynchium striatulum, commonly known as the Lesser Striated Feather-moss, is a species of bryophyte belonging to the Hypnaceae family. This moss is a fascinating component of forest ecosystems, contributing to ground cover and moisture retention. Its ecological role, though subtle, is vital for the health of its habitat. The physical characteristics of Plasteurhynchium striatulum are typical of many feather-mosses. It typically forms dense, soft mats or cushions on its substrate. The individual stems, often creeping or ascending, can reach lengths of a few centimeters. The leaves are small, ovate to lanceolate, and arranged in two ranks along the stem, giving it a flattened, feathery appearance. A key distinguishing feature, as suggested by its common name, is the presence of longitudinal striations or wrinkles on the leaf surface, which can be observed under magnification. These leaves are typically entire or finely serrated at the margins and possess a single costa (midrib) that extends partway up the leaf. Sporophytes, the reproductive structures, are rarely observed in this species. When present, they consist of a slender seta (stalk) supporting a capsule that contains spores. The capsules are typically erect and cylindrical, often with a distinct neck. Plasteurhynchium striatulum is native to a range that includes parts of Europe and Asia. It thrives in moist, shaded environments, commonly found growing on soil, decaying wood, and occasionally on rocks. Its preferred habitats are temperate forests, woodlands, and damp ravines where humidity is consistently high and direct sunlight is limited. Cultivation requirements are not typically considered for this wild moss, as its ecological niche is specific and difficult to replicate outside its natural environment. It requires consistent moisture, shade, and a stable substrate. While Plasteurhynchium striatulum does not possess widely recognized ornamental, agricultural, medicinal, or culinary uses, its ecological significance is noteworthy. As a ground cover, it helps to stabilize soil, prevent erosion, and retain moisture, creating a more favorable microclimate for other organisms. It contributes to the biodiversity of its habitat by providing a substrate for small invertebrates and other epiphytic organisms. Interesting adaptations of this moss include its ability to survive periods of desiccation by entering a dormant state, resuming growth when moisture becomes available. The striations on its leaves may play a role in water retention or light capture, though further research would be needed to confirm specific functional benefits. The intricate structure of its growth habit also contributes to the complex microhabitats found within forest floors.