Protolepidodendron

1. Protolepidodendron
Presented by : Salvi Pinky P.
M.Sc sem - 1
Paper - CBO : 402
Department of Life sciences,
H.N.G.U., Patan

2. Content
 Introduction
 General features
 Stem

3. Introduction
• The protolepidodendrales are a group of mostly
small herbs known from the Devonian and
Mississippian.
• As their name suggests, they are lycophytes,
related to the giant scale trees of the
Carboniferous.
• Unlike all other lycophytes however, the
protolepidodendrales bore leaves which were
forked at the tips.

4. • A few are believed to have had multiple sporangia on
each fertile leaf, such as the genus Estinnophyton,
though three are some who suggest that this plant is
actually a trimerophyte.
• The best known protolepidodendrid is Leclercqia, a
plant which is known to have grown to at least a half –
meter tall.
• Protolepidodendrales fossils are known from North
America, Europe, China and Australia by the Middle
Devonian, suggesting​ that they originated earlier.
• By the middle of the Carboniferous, they were extinct.

6. General features
• Protolepidodendrales are the group of fossil herbaceous
homosporous plants​ having subterranean, aerial
dichotomously branched axes, covered with ligulate or
eligulate microphylls.
• The group had an apparently world wide distribution during
Devonian and early Carboniferous periods​.
• They were probably ancestral to later lycophytes like
lepidodendrales and selaginellales.
• Protolepidodendron represents the type genus of this group.

7. • Baragwanathia longifolia from Silurian of Australia
along with Yarravia is the oldest fossil which can be
assigned under protolepidodendrales.
• The plant body of Baragwanathia longifolia is slightly
larger than modern day laycopods.
• Sporangia are reniform, found in association with
ordinary leaves present in certain area of stem
representing cone of the plant.

8. • Plants of protolepidodendron were of about 30
meters hight and 1 cm in diameter.
• Plant body consists of both prostrate as well as
aerial axes.
• Like other laycopods whole plant body is covered
with small leaves which are bifurcated at their
apices, a unique feature of protolepidodendron
leaves.
• Some of the leaves have redially elongated
sporangia on their upper surface.

10. • The ligules suggest that the
protolepidodendrales are
close relatives of
lepidodendrales,
selaginellales and
isoetales,all of which have
ligules as well.
• Leclerquia complexa is the
earliest known lycophyte
with ligules.
• Protolepidodendron
specimen from the upper
Devonian of New York,
with cm scale.

11. Stem
• The​ stem is covered with slender leaves.
• Stems assigned to the protolepidodendrales range
from 0.3 to 3 cm in diameter.
• Anatomically stem stele is star shaped, Action
stele, similar to Asteroxylon.
• Triangular protostele is found in the stem which is
uncommon among modern laycopods.

12. Protolepidodendron stem

13. References
• Botany For Degree Student Pteridophyta by :
P.C.Vashishta, A.K.Sinha, Anil Kumar
 https://acrobat.adobe.com
 https://it.m.wikipedia.org
 https://en.m.wikipedia.org

14. THANK YOU