Division LYCOPODOPHYTA - the Clubmosses, Spikemosses and Quillworts

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Division LYCOPODOPHYTA - the Clubmosses,
Spikemosses and Quillworts
Although there is great diversity within this
division, the following features are common to
all members Leaves are vascularized, with a
single vein Leaves are MICROPHYLLS, i.e. their
leaf traces do not leave a leaf gap in the
vascular cylinder They have true roots
The sporangia are intimately associated with
fertile leaves known as sporophylls
A and C show longitudinal and cross sections of a
stem with microphylls, B and D the same for
megaphylls
Evolutionary origin of a microphyll according to
the enation theory
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Morphological Diversity within the Lycopodophyta
Order ISOETALES
Order SELAGINELLALES
Order LYCOPODIALES
Lycopodium clavatum Running Clubmoss
Selaginella apoda Meadow Spikemoss
Isoetes sp. Quillwort
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Order LYCOPODIALES - the Clubmosses
Problems of Nomenclature
At one time, the Lycopodiales contained a
single genus - Lycopodium. Fairly recently,
taxonomists have split off several new genera
(n.b. splitters vs lumpers) n.b. new
names are not necessarily new, but are the result
of observing the principle of priority as
stated in the International Rules of Botanical
Nomenclature In this course, all clubmosses
will be referred to as Lycopodium, but with the
new name also given where it exists
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Some Club Mosses Commonly Seen in Northern Ontario
Note that the strobilus is born directly on the
leafy stem (i.e. no strobilophore)
Constrictions indicate annual growth
Lycopodium annotinum Bristly Club
Moss.
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Lycopodium clavatum - Running Clubmoss
Branching, prostrate sterile stems
Long, inward-curled leaf tip bristles
Long, branched strobilophores
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The Ground-Cedars
Branching ascendant, leaves bluish-green, ventral
leaves long
Branching flat, leaves green, ventral leaves short
Lycopodium (Diphasiastrum) tristachyum - Blue
Ground-Cedar
Lycopodium ( Diphasiastrum) complanatum -
Northern Ground-Cedar
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The Tree Clubmosses
Lycopodium obscurum - Flat-branched tree clubmoss
Lycopodium dendroideum - Prickly tree clubmoss
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Lycopodium lucidulum(Huperzia lucidula) - Shining
Clubmoss
In this species there is no discrete strobilus -
sporophylls are in fertile zones between sterile
zones, and resemble ordinary leaves
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Lycopodium inundatum ( Lycopodiella inundata) -
Bog Clubmoss
Leaf--
Sporophyll--
Strobilus--
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Clubmoss Stems in Cross-Section, Showing
Protostele
Phloem
Xylem
Stele
Epidermis
Lycopodium (Diphasiastrum) complanatum Note the
large air species in the outer cortex and the
sclerenchyma in the inner cortex
Cortex--
Leaf traces
Lycopodium clavatum Note leaf traces
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Root of Lycopodium clavatum in Cross-Section
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Lycopodium - Strobilus, Sporophylls and Sporangia
Longitudinal section of strobilus
Sporophyll
Sporangium
Upper (adaxial) side of sporophyll
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Gametophyte diversity in Lycopodium spp.
Photosynthetic lobes
Gameto-phyte of L. inundatum
Fungal portion
Embryo
Subterranean gametophyte of L. annotinum
Antheridium
-Rhizoids
Archegonium
Meristem
Storage tissue
Sperm
Palisade tissue---
Hyphal tissue
Rhizoid
Longitudinal section of subterranean gametophyte
of Lycopodium complanatum
Longitudinal section of subterranean gametophyte
of Lycopodium clavatum
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Lycopodium - Young Sporophyte Still Attached to
Gametophyte
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Lycopodium - Complete Life Cycle (Moore)
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Lycopodium - Complete Life Cycle (Raven)
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Order SELAGINELLALES - The Spikemosses
Selaginellales share the following features
with Lycopodiales small,microphyllous leaves
strobili consisting of sporophylls each of
which bears a single sporangium on the adaxial
surface HOWEVER, a critical difference between
the Lycopodiales and the Selaginellales is the
fact that members of the Selaginellales are
heterosporous Another difference is that the
leaves of Selaginella are ligulate, i.e. each
bears a small tongue-like structure on the
adaxial surface
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Some Spikemosses Found in Northern Ontario
Selaginella selaginoides - Northern Spikemoss
(moist habitats)
Selaginella rupestris - Rock Spikemoss (dry
habitats)
Selaginella apoda - Meadow Spikemoss (moist
habitats)
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A Spectacular, Iridescent Tropical Spikemoss -
Selaginella wildenovii
Stem
--Strobilus (?)
Leaf
Rhizophore
Root
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Selaginella lepidophylla - The Resurrection Plant
Dry
Moist
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Cross Section of Stem of Selaginella kraussiana
c.s. stem
c.s. stele
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Why do Some Species of Selaginella Appear to
Have Two Steles?
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A Strobilus of Selaginella apoda
n.b. smaller dorsal leaves
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Microsporangium and megasporangium Distribution
in Strobili of Various Selaginella species
S. helvetica
S. kraussiana
S. inequalifolia
Unnamed species
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Microsporophyll and Megasporophyll of Selaginella
in Adaxial View
Microsporangium
Megasporangium
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Selaginella - Microspore and Megaspore Germination
Section of microspore showing small prothallial
cell
Microspore
Rhizoid
Microspore with partly exposed male gametophyte.
Note jacket cells and two antheridia
Archegonium
Prothallus
Megaspore wall
Embryo
Microspore with mature male gametophyte ready to
release sperms
B. Early megaspore germination. C. Prothallus
protruding. D. Two embryos developing
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Selaginella Life History (Moore et al.)
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Selaginella Life History (Raven et al.)