Funaria hygrometrica, commonly known as common cord-moss or bonfire moss, is a widespread species of moss found across diverse environments globally. Its name, Funaria, originates from the Latin word ‘funis’, meaning rope, referring to the way its stalk twists. The specific epithet ‘hygrometrica’ highlights the hygroscopic nature of its seta.
Characteristics and Identification
The gametophyte, the leafy green part of Funaria hygrometrica, forms small, dense cushions. Individual plants are small, around half an inch tall, with spirally arranged, sessile leaves that have a discernible midrib. When wet, the plant displays a bright green color.
The sporophyte is its most distinguishing feature. It consists of a long, slender stalk, known as a seta, which can range from 20 to 50 mm in length and is yellowish to reddish-brown. This seta exhibits a hygroscopic nature, twisting and curling in response to changes in humidity.
At the tip of the seta is an asymmetrical, pear-shaped capsule, about 3 mm long, which often hangs horizontally. This capsule is reddish-brown and develops deep longitudinal furrows when dry. The capsule’s mouth is oblique, and it possesses specialized peristome teeth arranged in two rows that twist as they dry to aid in spore dispersal.
Habitat and Distribution
Funaria hygrometrica has a cosmopolitan distribution, found across temperate and tropical regions. This moss is common in disturbed, nutrient-rich, and bare soils. It colonizes areas affected by human activity.
It thrives in moist crevices of soil, walls, or paving, found next to water taps, gutters, and drains. Its presence is notable on recently burnt ground, such as after bonfires or wildfires, where it colonizes the nutrient-poor top layer of the soil. This species is also common in gardens, cultivated lands, construction sites, and nurseries.
Life Cycle and Reproduction
The life cycle of Funaria hygrometrica, like other mosses, involves an alternation of generations, where a free-living haploid gametophyte alternates with a semi-parasitic diploid sporophyte. A haploid spore germinates, forming a filamentous structure called a protonema. This protonema then develops buds, which grow into the leafy green gametophyte, the dominant stage of the moss plant.
Funaria hygrometrica is autoicous; it bears both male (antheridia) and female (archegonia) reproductive organs on different branches of the same plant. The male antheridia are found at the apex of the main gametophyte shoot, while the female archegonia develop on lateral branches. Water is necessary for fertilization, as motile sperm released from the antheridia must swim to the egg within the archegonium.
Upon fertilization, a diploid zygote forms within the archegonium, which then develops into the sporophyte. This sporophyte grows, drawing nutrients from the gametophyte through a structure called a foot. The sporophyte matures into the distinctive long seta and pear-shaped capsule. Within the capsule, meiosis occurs, producing numerous haploid spores. As the capsule dries, the specialized peristome teeth at its mouth twist due to changes in humidity, facilitating the release and dispersal of the spores into the air.
Ecological Significance
Funaria hygrometrica is a pioneer species, among the first to colonize newly disturbed or barren ground. Its ability to quickly complete its life cycle enables rapid establishment in such environments. This colonization helps stabilize loose soil, reducing erosion and preparing the ground for other plant species.
The moss contributes to early soil development by trapping dust and organic matter, enriching the substrate. Its dense growth absorbs and retains water, benefiting small organisms and maintaining local moisture. The presence of Funaria hygrometrica also indicates disturbed or nutrient-rich soil conditions.