15:371 Plant Diversity - Midterm I

Lineage

• A sequence of populations from an ancestor

Taxon

• Species or group

Synapomorphy

• A shared derived character

  • E.g. Seeds in gymnosperms and angiosperms 

Inherited Character - Cuticle

• Found in ferns and seed plants 

Shared Character - Cuticle

• Found in ferns and seed plants 

Number of Topologies for Cladogram of 3 Taxa

• 3 topologies

Shares the Most Recent Common Ancestor with Angiosperms

• Gymnosperms

Bryophytes Classification

• Monophyletic clade

Seed Plants Classification

• Monophyletic clade 

Main Branches on Family Tree of Land Plants 

• Liverworts

• Hornworts

• Lycophytes

• Ferns

• Gymnosperms

• Angiosperms 

Synapomorphies for Vascular Plants

• Branched sporophytes 

• Lignin

• Sclerenchyma

• Xylem & Phloem

• Roots

• Endodermis 

Synapomorphies for Seed Plants

• Seeds

• Pollen

• Heterospory

• Reduced dependant gametophytes 

Topologically Identical Cladograms

• Can be superimposed after pivot adjustment and removal or addition of elbows 

Plant Habit

• The growth form of plants

Phylogeny

• The evolutionary history of a group of organisms

Classification

• To group or organize 

Microphylls General Characteristics

• Always simple

• Never compound

Nomenclature

• Naming of the plant or group

Types of Leaf Arrangements

• Whorled 

• Opposite

• Alternate

Authority for Alfalfa 

• L.

  • Represents Linnaeus

Rank of Classification Noted by the Ending “-aceae”

• Refers to the family of the organism 

Psilotum Synangia

• Trilobate

Tmesipteris Synangia

• Bilobate

Specific Epithet

• Refers to the second part of the organisms two-part name

  • E.g. Homo sapiens, sapien is the _______

Key Purpose

• Used in the identification of organisms 

Rank of Classification Noted by the Ending “-ales”

• Refers to the order of an organism

Example of a Character in Plants

• Flower colour

Psilotaceae - Lacking of Leaves

• Leaves are reduced to enations due to evolutionary simplification

  • Aka reductions 

Two Genera That Possess Similar Synangia

• Psilotum

• Tmesipteris

Endospory

• Refers to the characteristic of the gametophyte forming in the spore 

Location of the Female Gametophyte Inside the Carpel

• Within the ovule

  • Which is found within the ovary, the lower part of the carpel 

Horsetail Gametophyte

• Small green structure that will generate the gametangia

• Embryo from this structure will create the sporophyte

Desiccation Resistant Character Seen in All Land Plants

• Possession of a cuticle

Embryo

• Multicellular structure that develops from a fertilised spore

• Often contained within a seed

Age of Land Plants

• ~460 million years old

  • Ordovician period

Shared Inherited Character of Land Plants

• Possessing the pigment Chlorophyll a

Plant Possessing Pendulous Sporophyte(s)

• Sphagnum moss

Alternation of Generations

• The diploid and haploid generations of an organism rotate in sequence

Traits Synapomorphic for Land Plants

• Cuticle 

• Embryo

Product That the Sporophyte Creates Via Meiosis

• Spores

Parts of a Seed

• Embryo

• Endosperm

• Seed coat

Parts of a Moss Sporophyte

• Foot 

• Seta

• Capsule

Advantages of Being a Sporophyte

• Production of spores through meiosis with genetic recombination and variation

• Usually larger and more complex, and are independent from gametophytes in many plants 

Embryophytes

• Another name for the land plants 

Costa

• The midrib or central vein

  • Usually used when referring to mosses

Leafy Liverwort Leaf

• Are small and in a flat sheet

• No midrib

• Sheet/leaf is one-cell thick

Pyrenoid

• Structure found inside the chloroplast

• Found in certain algae and some non-vascular plants

• Functions in concentrating CO2 near the Rubisco enzyme 

Where Rubisco is Located in Land Plants, Except in Hornworts

• Found in the chloroplast stroma

Where Rubisco is Located in Hornworts

• Within the pyrenoid 

Gemmae

• Small reproductive structure involved in asexual vegetative reproduction

• Especially notable in Liverworts as they present as splash cups 

Leafy Liverwort Sporophyte

• Consists of foot, seta, and capsule

• Dependant on gametophyte for nutrition

• Opens up by operculum to release spores

Hornwort Sporophytes

• Nutritionally independent 

Land Plant That Lacks a Stoma

• Liverworts

  • Instead has air pores on the surface of the thallus

Genus of Moss That has Cells Inflated with Water

• Sphagnum

Protonema

• Early, filamentous stage in the life cycle of mosses

• Enables for the growing gametophyte to gain a foothold on growing surface

Chloroplast Reversal in Hornworts

• Possesses a single massive chloroplast with a pyrenoid within

  • Considered primitive in comparison to other plants 

Items Inside the Marchantia Capsule

• Spores

• Elaters

Anthoceros Involucre

• Gametophyte 

• Tubular sheath that protects the base of the “horn”

Location of Hyaline Cells of Sphagnum

• Branch leaves

• Stem leaves

• Stems

Porella General Characteristics 

• Type of leafy liverwort

• Has 3 rows of leaves 

Protoxylem Appearance

• Narrow, elongated cells with a ring or spiral thickened walls 

Cell Wall that Becomes Lignified

• Secondary cell wall(s) 

Tracheary Elements that Lack Perforation Plate

• Traechids

Location of Fibres & Sclereids

• Sclerenchyma

• Xylem & Phloem

Structure Distal to the Root Apical Meristem

• Root cap

  • Within the root tip

Where Vascular Tissue is Located in Cross-Section of Root(s)

• In the centre core, forming a stele

Cell Layer Where Casparian Strip is Located

• Endodermis

Cell Layer Where Lateral Root(s) Emerge

• Endodermis

  • Specifically, the pericycle 

Function of Root Hairs

• Increases surface area to help with gathering nutrients, especially phosphates

• Water absorption

Cross-Section of a Vascular Leaf

• Upper epidermis - provides protection (top)

• Palisade mesophyll - responsible for photosynthesis

• Spongy mesophyll - facilitates gas exchange for photosynthesis and respiration

• Vascular bundles - where xylem and phloem are, provide structural support

• Lower epidermis - contains stomata for gas exchange, with guard cells (bottom)

Functions of the Root Cap

• Lubricates

• Protection

• Sense gravity

Pith

• Central region of a stem or root

• Made up of parenchyma cells

• Functions in storage of nutrients 

Pit

• Thin region or gap in the secondary cell wall of a plant cell 

• Allows transportation of water, minerals, and other molecules

Components of Treachery Elements

• Tracheids

• Vessel elements

Function of the Casparian Strip

• Regulates the movement of water and dissolved substances into the vascular tissue (xylem) of the roots 

Microphyll and/or Lycophyll General Description

• Simple leaf with a single vein

• Not branched

Stele Type in Lycophyte Stems

• Protostele

Habitat for Isoetes

• In margins of lakes, rivers, and along the shores of bodies of water

Homosporous

• To have one type of spore

Sporangia in Huperzia

• Located on the upper (adaxial) surface of the sporophylls

Type of Slit in Club-Moss Sporangium 

• Transverse slit (horizontal) 

Isoetes Ligule

• Structure that points/goes in upwards

Isoetes Sporophyll

• Structure that points/goes downward 

Trilete Mark

• Y-shaped scar on the female spores (of certain lycophytes)

Lycophyte Family that is Homosporous

• Lycopodiaceae 

Club-Moss Genus Possessing Strobilus & Linear Leaves

• Lycopodium

Lycophyte Genera Possessing Ligules on Both Leaves & Sporophylls

• Isoetes

• Selaginella 

Selaginella Sporangium

• Megasporangia

• Microsporangia

Sporophyll

• Leaf or leaf-like structure that bears sporangia 

Genus of Club-Moss Possessing Scale-like Leaves Laid on top of Stems 

• Selaginella

Species of Spike Moss With Dimorphic Leaves

• Selaginella apoda

Phloem in a Dictyostele

• Located between the individual vascular bundles

Euphyll

• Flattened branch stem systems

• Large and complex

• In most vascular plants

Lycophyll

• Simple outgrowth

• Single and unbranched

• Small and narrow

• Found in lycophytes 

Changes a Siphonostele into a Dictyostele

• Interruptions or gaps (leaf gaps) in the vascular cylinder 

Gametophyte of Whisk Ferns & Ophioglossid Ferns

• Mycotrophic 

• Without chlorophyll 

Seen in Frond of Ophioglossaceae

• Frond divided into sterile segment and fertile segment

Type of Sporangium in Angiopteris & Botrychium

• Leptosporangia 

  • Which are sporangia that develop from a single initial cell and have a thin wall 

Location of Bifid Appendage in Psilotaceae

• Synangium 

Where the 30 Kbase Inversion is Located 

• Chloroplast