Tetraphis pellucida Hedw.

Scientific Name and Native Range

Tetraphis pellucida Hedw. is a moss native to the Northern Hemisphere that grows almost exclusively on rotten stumps and logs.

Shoot Height

Its leafy shoots grow 8 to 15 mm tall.

Leaf Size

Lower leaves measure 1 to 2 mm long, while upper leaves and perichaetial leaves (the leaves that surround archegonia) reach 3 mm long.

Leaf Margins

All leaves have smooth, entire margins.

Reproduction Methods

This moss reproduces both asexually via gemmae and sexually via spores produced by a sporophyte.

Asexual Reproduction Structures

For asexual reproduction, Tetraphis pellucida produces specialized reproductive propagules called gemmae, which grow in one of two structures: gemma cups or stalks.

Gemma Cup Structure

Gemma cups are formed from three to five larger specialized leaves, and hold gemmae in their center.

Stalk Gemma Structure

Stalk gemmae are held in a terminal cluster on a small microphyllous stalk that extends 1 to 4 mm above the leafy gametophyte.

Gemma Dispersal Mechanism

Gemmae are most commonly dispersed by energy from falling rain.

Gemma Cup Dispersal Function

The shape of gemma cups lets them capture the impact energy of raindrops to propel gemmae outward.

Rain Dispersal Distance

On average, gemmae from gemma cups travel 19.5 mm, while gemmae from stalks travel 13.3 mm.

Disturbance Dispersal Distance

When gemmae are displaced by disturbance, cup gemmae travel an average of 12.1 mm, while stalk gemmae travel an average of 16.9 mm.

Sexual Reproduction Breeding System

For sexual reproduction, Tetraphis pellucida is dioicous, meaning antheridia (male reproductive structures) and archegonia (female reproductive structures) grow on separate gametophores.

Sporophyte Development

After fertilization of an archegonium, a sporophyte develops.

Mature Sporophyte Morphology

The mature sporophyte has a 6 to 14 mm long seta, a 2 to 3 mm long capsule, and a 1 mm wide operculum.

Capsule Peristome Features

The fully developed capsule has four peristome teeth attached to its rim.

Spore Characteristics

Spores that develop inside the capsule are either smooth or finely roughened, and measure 10 to 13 micrometers across.

Reproduction Strategy Trigger

Whether a Tetraphis pellucida colony uses asexual or sexual reproduction depends on shoot density.

Low Density Reproduction

At low densities (fewer than 70 shoots per cm²), colonies produce no sporophytes, and all shoots are gemmiferous (gemma-producing).

High Density Reproduction

At densities over 70 shoots per cm², gametophores begin to develop, and at densities of 190 shoots per cm², colonies produce no gemmiferous shoots at all.

Gametophore Density Variation

At medium densities, archegoniophores (gametophyte shoots bearing archegonia) are more common than antheridiophores (gametophyte shoots bearing antheridia); as density increases further, antheridiophores become far more numerous than archegoniophores.