Lab Week 3: Lycophytes and Monilophytes

Which came first: the Lycophyte or the Monilophyte?

Lycophytes

Lycophytes

oldest group of vascular plants; contains club mosses, spike mosses, and quillworts; lacks seeds

Monilophytes

Ferns, horsetail, and whisk fern: monophyletic clade meaning they all share a common ancestor

Microphyll

Unbranched vascular tissue characteristic of lycophytes

Megaphyll

True leaves with branched vascular tissue; marked the branching of monilophytes

Strobili

cone-like structures containing sporangia

Heterospory

Derived trait meaning to produce two types of spore: the megaspore and microspore. This trait is present in Isoetaceae, Selaginellaceae, and Water Ferns

Psilotaceae

Whisk ferns; homosporous; no true roots or leaves JUST STEMS! Sporangia fused into synangia

Isoetaceae

quillworts

Salviniales

water ferns

Homospory

Ancestral trait; produces one type of gametophyte. This trait is present in Lycopodiaceae, psilotaceae, ophioglossaceae, equisetaceae, marattiaceae, and most polypodiidae

Megaspores

develop into female gametophytes (eggs)

microspores

develop into male gametophytes (sperm)

Selaginellaceae

spike mosses; heterosporous, with sporangia at the bases of sporophylls atop the plant.

Synangia

A group of fused sporangia

Ophioglossaceae

Grape ferns; leaves arranged in two sections: a photosynthetic trophophore and a sporangia-bearing sporophore

trophophore

sterile, photosynthetic

sporophore

fertile, sporangia-bearing part of the plant

Marattiaceae

Marattoid ferns; homosporous; eusporangiate; contains synangia

leptosporangiate

sporangia arise from a single cell

eusporangiate

sporangia arise from multiple cells

water ferns

heterosporous; adapted to float on water; special cavities for nitrogen-fixing cyanobacteria

sori

clusters of sporangia

indusia

cover sori (a.k.a.covers clusters of sporangia)

pinnate

leaflets arranged on either side of the stem, typically in pairs opposite each other

Which trait do Isoetaceae, Selaginellaceae, and Water Ferns share?

Heterospory

dimorphic fronds

characteristic of some ferns exhibiting sexual dimorphism (males and females different); one frond fertile, one frond is sterile