Mitthyridium undulatum

Click the yellow dot to see these synapomorphies (click any yellow dot to see a clade's characters)

Gemmae characters: gemmae smooth

Margin characters: number of border cell columns evolves from 7 to 30+; margin involute/constricted

Leaf characters: leaf tip rhizoids present

Indel characters: indel 1, 2, 6 and 8 evolve.

Mitthyridium undulatum

Range Map

This clade is found in Malesia, Australia, and has undergone (is undergoing) a rapid radiation in the major islands of Fiji

Description

Lineage: Mitthyridium undulatum

Latin name: Mitthyridium obtusifolium (Lindb.) Robinson
Synonyms:
Codonoblepharum undulatum Dozy and Molk
Syrrhopodon adpressus Broth.
Thyridium geheebi (Par.) Fleisch.
Thyridium binsteadii(Ther. & Dix.) Broth.
Thyridium pungens (Dix.) Broth.
Mitthyridium adpressum (Broth.) Robinson

General description:
Plants medium sized and often shiny or glossy when dry. Branches to 4 cm long. Leaves typically 2.5 mm long, 0.8 mm wide across spreading shoulders (though not as spreading as fasciculatum). The lamina is triangular-lanceolate with acute or more commonly subulate; leaves are highly undulate. Stereome (border of hyaline cells) only very pronounced toward the leaf base and never more than 12 cell columns in width. Costa percurrent or ending just below the apex (as is typical of taxa in Mitthyridium). Laminal cells small (5-7 mm wide), as is also common in Mitthyridium. Cancellinae typically occupying 1/5 the leaf length and composed of many, 25-28, cell columns. Sporophytes are occasioinal; seta length ca. 1 cm.

Diagnostic phylogenetic characters: [move the cursor over the image to view the morphological matrix]

Gemmae texture is rough. The number of cancellinae cell columns is high (25-30). The % cancellinae is low, 1/5-1/6 the total leaf length (as found in the luteum group). The transition shape is a 4 (see glossary). The average number of border cells is 10. The leaf apex is often strongly subulate (pinched dramatically at apex, forming a proboscoid tip). The papillae are large and often obscure the laminal cell outlines.

There is an weakly supported but "emergent" monophyletic group within undulatum that bears characteristics often attributed to Mitthyridium adpressum, which is here considered synonymous with undulatum. Despite the genetic distinctiveness, adpressum is not sufficiently obvious morophologically and was thus considered synonymous with undulatum.

Diagnostic phylogenetic characters (synapomorphies and/or autapomorphies) were assessed by optimizing via ACCTRAN morphological characters to the 80 taxon total evidence phylogeny decribed in the Phylomonography&Mitthyridium section bulleted above.