Note the dichotomous branching pattern (ie. one branch give rise to 2 branches) on this Psilotum.
Synangium is the structure formed by the fusion of 3 sporangia. You can still see the 3 thirds of sporangia.
Psilotum has protostele vascular tissue arrangement.
The ring of blue-staining cell walls is the Casparian strip. These cells have lignin and/or suberin in their cell walls to prevent apoplastic movement of water and nutrient.
The fronds (also known as leaves) of Ophophioglossum sp. are made of 2 parts: a sterile blade and a fertile segment with 2 rows of eusporangia.
Cross-section through eusporangia of Botrychium. Note the homosporous spores (spores of the same size).
Rhizome cross-section of Botrychium.
A fern from Pacific Spirit Park. The central 'stem' (in red) that runs throughout the frond is the rachis. Deriving from the rachis are pinna (in blue). And the smaller divisions coming from the pinna are the pinnule (in yellow). The bottom half of the rachis without any pinna attached is the petiole (not shown here).
Some ferns don't have pinnules in their fronds and instead they end in pinna as in this sword fern.
Sword fern's name came from its pinna that resemble swords (complete with hilts and blades).
Polypodium vulgare (licorice fern).
The scattered nodes of previous leaf attachments. Some leaves can arise from the bottom side of the stem and twist its way toward the sky.
Pteridium rhizome cross-section (1 of 4). Pteridium is amphiphloic and has dictyostele with 2 rings of vacular bundle. The bundles aboves are part of the outer ring.
(2 of 4) As we move inwards we see the second ring.
(3 of 4) The first half of the inner ring.
(4 of 4) The two halves of the inner ring.