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Family: Salviniaceae

Kingdom: Plantae Rank: Family Parent: Hydropteridales Status: Valid

Common Names:

  • FLOATING FERN FAMILY - English, United States of America
  • WATER-SPANGLE FAMILY - English, United States of America

Morphological Description

Family Recognition in the Field: Small free-floating aquatics with leaves in groups of three (two leaves floating, nearly rounded to elliptic, entire, with conspicuous branched hairs; one leaf submerged, finely dissected, root-like).

Other

Notes: A very small family (1 genus, ca. 10 species) of heterosporous (= with 2 spore types) aquatic ferns found mostly in the tropics, but ranging from s U.S., Mexico, West Indies, Central America, and South America to Eurasia and Africa, including Madagascar (Nauman 1993d). The Azollaceae has often been included in the Salviniaceae, but according to Lumpkin (1993), the relationship is not close enough to warrant inclusion in the same family. However, molecular evidence does indicate that Salvinia and Azolla are each other’s closest living relative (Hasebe et al. 1995), and the two families are probably appropriately treated in the same order (Schneller 1990b). Three families of heterosporous water ferns occur in East TX (Azollaceae—Azolla, Marsileaceae—Marsilea, Pilularia, and Salviniaceae—Salvinia). These groups are quite distinct morphologically, and traditionally the marsileaceous (Marsilea and Pilularia) and salviniaceous (Azolla and Salvinia) lines were considered to have evolved independently from different homosporous fern ancestors. However, all three living heterosporous water fern families appear to comprise a monophyletic group as suggested by recent morphological, fossil, and molecular evidence (Rothwell & Stockey 1994; Hasebe et al. 1995; Pryer 1999).