What are some features of the lycopsids?
Lycopsids are distinguished from other lycophytes because they posses spirally arranged microphylls (narrow, spine-like leaves supplied with a single, unbranched vein) and adaxial sporangia. (Intermediate forms such as Asteroxylon and Drepanophycus are commonly referred to as pre-lycopsids.)
What is an example of Lycophyte?
Lepidodendron
IsoetalesSigillariaSelaginellaceaeHuia
Lycophyte/Lower classifications
Are lycopsids extinct?
The giant lycopsids died out in the Late Permian, near the end of the Paleozoic Era, which ended about 250 million years ago. The last of them lived in what is now China, in swampy wetlands much like those of Illinois many years before.
What did lycophytes evolve into?
Evolution of lycophytes Lycophytes are believed to be the oldest living lineage of vascular plants. Estimates of their evolution date back to more than 400 million years ago during the Silurian Period, long before gymnosperms and angiosperms.
How do you identify a Lycophyte?
The distinguishing features of the lycophytes are the arrangement of their vascular tissues and their leaves—microphylls with only a single vascular strand. The sporangia on the modern plants are kidney-shaped, like those of the ancestral forms, and borne on sporophylls clustered in strobili.
Do Psilophyta have leaves?
Phylum Psilophyta. They look very similar to 400 million year old fossils. They have no roots or leaves, just a photosynthetic stem. They can either grow in the ground or be epiphytes (growing on the stem or branches of another plant).
What makes the Silurian period unique?
Possibly the most remarkable biological event during the Silurian was the evolution and diversification of fish. Not only does this time period mark the wide and rapid spread of jawless fish, but also the appearances of both the first known freshwater fish and the first fish with jaws.
What kind of root structure does a lycopsid have?
They had rhizomous rooting structures, dichotomous branching and were probably homosporous. At least one species, Leclercqia complexa, possessed ligules (tiny flaps of tissues attached just above the microphyllous leaves), a feature also found in spike mosses, arborescent (tree-like) lycopsids and quillworts.
How are club mosses related to the lycopsids?
It’s a herbaceous plant that appears to be most closely related to the modern day club mosses (e.g., Lycopodium ). Club mosses are homosporous (they produce uniformly-sized bisexual spores). This condition, which is believed to be primitive, was probably also present in the earliest lycopsids.
What kind of tree did the giant lycopsids have?
In some cases, as at Riola, the giant lycopsid trees may have pushed through and towered over a much lower canopy of tree ferns and seed ferns, smaller trees and shrubs that were more like what we think of as trees today. The main support tissue in the giant lycopsids was bark instead of wood.
How are lycopsids related to other extinct groups?
Lycopsids are related to several extinct groups, including Cooksonia (some, but not all species), Asteroxlon, Drepanophycus, zoosterophylls and barinophytes, through the possession of sporangia (spore-bearing organs) that are stalked and kidney-shaped (reniform).