Selaginella: Plants Related to Ferns
The genus Selaginella does not belong among the genuine ferns but with the Sellaginellaceae (fern-like plants). This class developed its wide range of shapes and forms millions of years ago. As well as the 40 m (130 ft) tall scale and seal trees that belong in this class, and which dominated the forests of the carboniferous age, there were also some leafy species. It is quite astonishing to think that members of the genus Sellaginella (club mosses) still in existence today resemble plants that first developed about 350 million years ago.
Of the approximately 700 species known, only two are indigenous to the Alps of central Europe; the others originate mostly from the tropics.
The shoots of club moss are usually branched in forks and covered in four rows of scale-like tiny leaves. In the case of species that grow in a creeping fashion, they soon form a green carpet. In many species, light-coloured, leafless shoots emerge from the branching of the stalks. Roots will grow from these.
The spore-bearing leaflets of the club mosses form four-sided, terminal spikes. Each spore leaf carries only one spore capsule which is formed where the leaf emerges. Male sporangia with many minute and female ones with four large are produced and grow together on one spike. The development of both male and female cells begins before the have left their capsules. The genus is very variable. In addition to low-growing, prostrate types there are also upright or even climbing ones. Leaves appear in all shades from yellow to bright green and blue green. There are also white/green and yellow/green variegated types. Those most frequently found in the gardening trade are Selaginella apoda and varieties of Selaginella kraussiana as well as Selaginella martensii.
• Selaginella apoda from North America is very low-growing and looks like a moss.
• Selaginella kraussiana originates from tropical and southern Africa. It forms dense carpets with its prostrate, 30 cm (12 in) long branches.
• Selaginella martensii, from Mexico, grows upright and is supported by strong roots. It can grow up to 30 cm (12 in) tall.
• Selaginella gracilis comes from Polynesia. It can grow up to 90 cm (36 in) tall but still looks very dainty.
• Selaginella willdenowii from tropical Asia can climb up to several metres using its protruding frond shoots. It has blue-green fronds.
Origin: Tropics, subtropics and temperate regions. Mostly in tropical rainforests, more rarely in dry regions.
Position: Most species offered for sale as indoor plants require shade or semi-shade, even temperatures all year round and high humidity. Protect from draughts.
Care: Keep evenly moist. Avoid water-logging. Never allow the rootstock to dry out; the plants will not usually recover from this. Give low doses of fertilizer from the first month of spring to the first month of autumn. Spray frequently.
Propagation: From branch tips that can be pinned down to compost or from division. Some species can be propagated from young plantlets that form on the leaves.
Pests, diseases: None known.
My tip: Club mosses are very suitable as an underplanting for larger ferns. Small species grow well in bottle gardens.