Radula complanata (Flat-leaved Scalewort)

Radula spp.

Native to North America

Overview

Radula spp. is a large genus of leafy liverworts in the family Radulaceae, with roughly 200 species distributed worldwide. Plants form flat, closely appressed patches or thin mats of green to yellow-green or brownish shoots 0.4-3 inches (1-8 cm) long, the branches spreading in one plane against bark, rock, or living leaves. Leaves are arranged in two overlapping ranks, each divided into a larger rounded upper lobe and a much smaller lobe, the lobule, folded against the underside of the stem; underleaves are absent. Rhizoids arise from the lobules rather than directly from the stem, a feature that helps define the genus. Many species reproduce by disc-shaped gemmae shed from leaf margins as well as by spores released from short-lived capsules held in a flask-shaped perianth. Shoots are thin and somewhat translucent, drying to a darker film that swells and greens within minutes of wetting. Colonies enlarge slowly over years and persist on stable surfaces. Most species depend on steady humidity; shoots shrivel in dry air and revive when rewetted, and prolonged sun or drying ends a colony.

Native Range

Species of Radula spp. occur on every continent except Antarctica, with the greatest diversity in moist tropical and oceanic temperate regions. Plants grow mainly as epiphytes on tree bark and leaves, and on shaded, humid rock, from coastal forest to montane cloud forest.

Suggested Uses

Encountered as bark and rock epiphytes in woodland and forest, and occasionally kept in shaded terrariums and vivariums on wood or stone. Establishment depends on high humidity and shade, and colonies decline in dry or exposed positions.

How to Identify

Identified by flattened shoots with leaves in two ranks, each leaf carrying a small lobule folded beneath the larger lobe, and no underleaves along the stem underside. Rhizoids emerge in tufts from the lobules rather than from the stem. The one-plane, appressed growth and disc-shaped marginal gemmae of many species separate Radula spp. from Frullania spp. and Porella spp., which have differently shaped lobules and underleaves.

Appearance

Size & Dimensions

Width/Spread1" - 8"

Colors

Foliage Colors

green

yellow green

Fall Foliage Colors

no change

Detailed Descriptions

Foliage Description

green to yellow-green or brownish

Growing Conditions

Sun Requirements

SunFull Shade

Tolerates up to 3 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 7.0(Acidic)

357912

Soil Types

rocky

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Plants persist on bark, leaves, and shaded rock in humid, sheltered sites. Steady humidity and shade support growth; shoots shrivel during dry air and revive after wetting. Direct sun and prolonged drying cause browning and colony loss. Detached shoots and gemmae re-establish on moist bark or stone kept shaded. Many species are sensitive to air pollution and to drying of the host surface.