selaginella

Spikemoss
Scientific classification
Kingdom:	Plantae
Division:	Lycopodiophyta
Class:	Isoetopsida
Order:	Selaginellales
Family:	Selaginellaceae
Genus:	Selaginella
Species
See text.

Curled up Selaginella tamariscina

Selaginella is a genus of plants in the family Selaginellaceae, the Spikemosses. Many workers still place the Selaginellales in the class Lycopodiopsida (often misconstructed as "Lycopsida"). This group of plants is included in what, for convenience, is called "fern allies". S. moellendorffii is an important model organism, and its genome was sequenced by the United States Department of Energy's Joint Genome Institute.^[1]

Characteristics

Selaginellas are creeping or ascendant plants with simple, scale-like leaves on branching stems from which roots also arise. The plants are heterosporous (megaspores and microspores), and have structures called ligules, scale-like outgrowths near the base of the upper surface of each microphyll and sporophyll.

Unusually for the lycopods, each microphyll contains a branching vascular trace.

Species

There are about 700 species of Selaginella, showing a wide range of characters; the genus is overdue for a revision which might include subdivision into several genera. Better-known spikemosses include:

• Selaginella apoda - Meadow Spikemoss (eastern North America)
• Selaginella bifida (Rodrigues Island)
• Selaginella braunii - Braun's Spikemoss (China)
• Selaginella bryopteris - Sanjeevani (India)
• Selaginella canaliculata - Clubmoss (southeast Asia, Maluku Islands)
• Selaginella densa - Lesser Spikemoss (western North America)
• Selaginella eclipes - Hidden Spikemoss (eastern North America)
• Selaginella kraussiana - Krauss's Spikemoss (Africa, Azores)
• Selaginella lepidophylla - Resurrection plant, Dinosaur plant, and Flower of Stone (Chihuahuan Desert of North America)
• Selaginella moellendorffii
• Selaginella rupestris - Rock Spikemoss, Festoon Pine, and Northern Selaginella (eastern North America)
• Selaginella selaginoides - Lesser Clubmoss (north temperate Europe, Asia and North America)
• Selaginella uncinata - Peacock Moss, Peacock Spikemoss, Blue Spikemoss
• Selaginella willdenowii - Willdenow's Spikemoss

Many species of Selaginella are desert plants known as "resurrection plants", because they curl up in a tight, brown or reddish ball during dry times, and uncurl and turn green in the presence of moisture. Other species are tropical forest plants that appear at first glance to be ferns.

Wallace's Selaginella (Selaginella wallacei)

References