Acrocarpous

Acrocarpous is a descriptive term in bryology used to classify mosses whose sporophytes are produced at the apex of the main shoot, rather than on lateral branches. The term derives from Greek acro- “tip” and karpos “fruit.”

In most acrocarpous mosses the growth form is tufted or cushion-like, with erect shoots rising from a relatively sparse, unbranched axis. The gametophyte often forms a compact center with leaves arranged around the stem, and the sporophyte is terminal on the main axis. The capsule (sporangium) is typically supported by a relatively long seta and may be immediately covered by a calyptra; capsule dehiscence and peristome teeth vary among species. In contrast, pleurocarpous mosses produce sporophytes on short, usually lateral branches and tend to creep along the substrate.

Ecologically, acrocarpous mosses are common in drier, exposed habitats or on well-drained soils and rocks, where their upright growth helps reduce shading and desiccation. They may tolerate periods of dryness and rapidly colonize open soils after disturbance. Taxonomically, the group is not monolithic but includes several families and genera, with Polytrichum and Bryum cited as typical examples. The distinction between acrocarpous and pleurocarpous is a traditional, functional one and some species show intermediate forms or variability with environmental conditions.