Mitthyridium subluteum

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 subluteum

Range Map

This clade is found in the Fijian islands and may be highly restricted in geographical range

Description

Lineage: Mitthyridium subluteum

Latin name: Mitthyridium subluteum (C.M.) Nowak
Synonyms:
Syrrhopodon subluteus C.M.

General description:

Plants more delicate than closely related luteum usually green in color. Branches small only to 2 cm long. Leaves 3 mm long, 1.0-1.5 mm wide, linear and straight. The lamina is triangular-lanceolate. Stereome (border of hyaline cells) only around the very base of the leaf next to the cancellinae. Costa percurrent or ending just below the apex. Laminal cells small (5-7 mm wide). Cancellinae typically occupying 1/6 of the leaf length and composed of 10 cell columns. Sporophytes unknown.

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

The characters that differentiate this lineage from its closest relatives, luteum, perundulatum, and jungquilianum are few. Still its distinctness as a unique monophyletic group is reasonably sufficient to warrant a name. This group has a significantly less cancellinar cell columns than its close relatives, on average 11 as compared with 15-19. The group is often noticeable by the presence of leaf base rhizoids. The group lacks an adaxial epidermis while most of its closest relatives do not.

General phylogenetic characteristics of the "luteum complex":
All of the groups in this linear leaf "luteum complex" (subluteum, jungquilianum, luteum, and perundulatum) except perundulatum have small cancellinae that occupy no more than 1/5-1/7 the total leaf length. All have state 1 for the shape of the transition from cancellinae to lamina. All except luteum have extensive serrations along the leaf margin. All have very few border cell columns (approximately 7 or less). All except perundulatum have a border that does not widen into the stereome characteristic of Mitthyridium until the very base of the leaf (state 5 or 6). All except perundulatum have an acute leaf apex.