Gleicheniales
Order Gleicheniales
Ecology & Form
These ferns are characterized by root steles having 3–5 protoxylem poles
Antheridia with 6–12 narrow, twisted, or curved cells in their walls
Their habitats are highly diverse, including plants with the typical fern fronds, others whose leaves resemble those of palm trees, and yet others again which have undivided leaves
They are tropical ferns, most diverse in Asia and the Pacific region.
Geologic Range
Triassic - present
Diversity
3 families (Dipteridaceae, Gleicheniaceae, and Matoniaceae)
10 extant genera (see families below)
~174 extant species
Dipteridaceae
Known as the umbrella ferns
2 extant genera (Cheiropleuria, Dipteris); ~10 extant species
The group is confined to Asia, New Guinea, and northern Australia
Middle Triassic of Italy, Australia, and Argentina
7 extinct genera (Hausmannia, Clathropteris, Dictyophyllum, Thaumatopteris, Camptopteris, and Polyphacelus)
Above: Dipteris conjugata
Gleicheniaceae
6 genera (Dicranopteris, Diplopterygium, Gleichenella, Gleichenia, Rouxopteris, Sticherus, and Stromatopteris) with 160 extant species
The most ancestral in the Hymenophyllales (Lehtonen 2011)
This family is found in both the Old and New World tropics
Stems
Long creeping rhizomes
Stems are typically protostelic, with some steles containing parenchyma
Leaves
Large fronds that are several times pinnate.
Branching of the fronds is distinctive due to the presence of a so-called resting bud, which is formed by rachial dichotomies in which one part of the rachis is temporarily arrested in its growth
Petiole vascular strands may be solid or C-shaped with enrolled ends
Reproductive features
Sporangia occur in ring-shaped sori on the abaxial surface of the pinnule and there is no indusium (exindusiate)
The number of sporangia per sorus is usually small, but in some species may be up to 15 sporangia
Pinnule segments in some species are greatly reduced and cup-shaped
The annulus is transverse to oblique
Above: Ferns in the Gleicheniaceae. A,B. Gleichenia microphylla. A. Leaf showing pseudodichotomous branching of segments. B. Close-up of leaf, abaxial surface with dense trichomes. C,D. Sticherus cunninghamii. C. Leaf with pseudodichotomous branching of segments. D. Close up of sori, each with 3-5 sporangia. E,F. Dicranopteris linearis. E. Long, sprawling, pseudodichotomously branching leaf rachis. F. Pinnule close-up, abaxial surface, showing sori, each with numerous sporangia. (Images C,D from Lawrence Jensen; F from Gerald Carr)
Matoniaceae
2 extant genera (Matonia and Phanerosorus); 4 extant species
This family is confined to Indonesia, Borneo, and New Guinea
Middle Triassic - present (Klavins et al. 2004)
8 genera (Laccopteris, Phlebopteris, Matonidium, Matonia, Microdictyon, Weichselia, Tomaniopteris, and Konijnenburgia); 26 species
Stems
The rhizome is covered by hairs
The anatomy consists of two or three concentric amphiphloic siphonosteles, with leaf traces produced from the outer cycle
Leaves
Leaves of Matonia are palmately-dissected
Phanerosorus leaves are pendulous and pinnate.
Reproduction
Sporangia are massive and arranged in a ring around a receptacle that is the stalk of a peltate indusium
The position of the annulus is oblique, and spores are trilete
Above: Matonia pectinata