Plantae

• Evolution of Land Plants

  • Plant adaptations to life on land include the development of many structures

  • A water repellent cuticle

  • Stomata to regulate water evaporation

  • Specialized cells to provide rigid support against gravity

  • Specialized structures to collect sunlight

  • Alternation of haploid and diploid generations

  • Sexual Organs

  • Dispersal Mechanisms
• Bryophytes: Spore-Bearing, Non-vascular

  • Derived from A Greek word “Bryon” which means Mosses and “Phyca” meaning plant.

  • Oldest plants on Earth- 400 million years or more.

  • Bryophytes do not have true vascular tissues.

  • Lack leaves; they have leaf-like scales
• Bryophytes

  • They lack true roots; root-like structures called rhizoids.

  • Lack true stem

  • Ground-hugging

  • No lignified tissues

  • Moist and humid environment

  • Autotrophic & Saprophytic
• Bryophytes

  • Three Divisions

  • Division Hepatophyta (Liverworts)

  • Division Anthocerophyta (Hornworts)

  • Division Bryophyta (Mosses)
• Bryophytes

  • Division Bryophyta (Mosses)

  • Body of the moss is usually leafy-like

  • Prefer in damp, shaded locations in temperate zones

  • Dioecious

  • Usually 1-10 cm tall

  • Female mosses produce sporangia born on stalks on the tip of the thallus.
• Mosses: Common Genera

  Polytrichum

  Sphagnum

  Fissidens

  Mnium

  Pogonatum

  Thuidium
• Bryophytes

  • Division Hepaticophyta (Liverworts)

  • Small, 2-20 mm wide, less than 100 mm

  • Common form:

  • protrate, flattened, ribbon-like or branching structure (thallus)- thallus liverworts

  • flattened “stem” with overlapping scales or leaves in three ranks- leafy liverworts
• Liverworts: Common Genera

  Marchantia

  Riccia

  Cyathodium

  Plagiochila

  Bazzania
• Bryophytes

  • Division Anthocerophyta (Hornworts)

  • Grow as a thin rosette or ribbon-like gametophyte thallus

  • Unique feature- erect, photosynthetic, horn-like sporophytes arising from thallus

  • Some can live with association of Nostoc
• Hornworts: Common Genera

  Anthoceros

  Phaeoceros
• Lycophytes: Lycopodiaceae (Club Moss)

  • Lycophylls=microphylls- unbranched
  • Sporangia develop laterally (relative to the stem) in the axils of specialized leaves termed sporophylls
  • Aggregate of sporophylls with associated sporangia, is known as a strobilus or cone.
• Lycopodiaceae: Common Genera

  • Lycopodium casuarinoides Spring
  • Huperzia phlegmaria (L.) Rothm
  • Lycopodiella cernua (L.) Pic.
• Selaginellaceae

  • Spirally arranged vegetative leaves that are isomorphic.
  • Single genus: Selaginella (Spike Moss)
  • Heterosporous, endosporic, ligule in the leaf.
• Isoetaceae

  • With a small corm-like stem that has roots attached below and leaves above.
  • Isoetes (Quillworts)
• Monilophytes

  • Spore-bearing, vascular, non-flowering
  • Megaphyllous, lamina is traverse by many veins and usually large.
  • Curling of young frond forming fiddle heads or croziers or circinate vernation.
  • Sporangia born on sori (sorus) usually found in the lower part of the leaves.
• Monilophytes

  • 5 Major lineages

  • Equisetales

  • Maratiales

  • Polypodiales

  • Ophioglossales

  • Psilotales
• Ophioglossales

  • Fronds consists of a sterile segment, which contains the photosynthetic blade or lamina, and a fertile segment.

  • The underground rhizome gives rise to unbranched roots that lack root hairs.

  • Botrychium (grape fern or moon wort); Ophioglossum (adder’s tongue fern)
• Psilotales

  • All psilophytes lack true roots, an apomorphy for the group

  (only absorptive rhizoids arise from the rhizome)

  • Leaves of psilophytes are very reduced and peglike and may lack a vascular strand

  • Fused synangium, with forked appendage
• Equisetales

  • Ribbed Stems
  • Reduced, whorled leaves that are usually marginally fused
  • Sporangiophores
  • Photosynthetic spores with elaters
• Marattiales

  • The sporangia are fused into a common structure, a synangium

  • A distinctive apomorphy of the Marattiales is the occurrence of a polycyclic siphonostele
• Polypodiales

  • Leptosporangiate Ferns

  • Horizontal stem- rhizome

  • Leaf= frond; Petiole= stipe

  • Ultimate leaflets or blade divisions are called pinnules
• Origin of Megaphylls (Euphylls)

  • Three distinct types of homoplasic (analogous) structures called leaves occur in plants

  (1) leaves on gametophytes of non-vascular plants;

  (2) enations/microphylls of zosterophyllophytes and lycophytes; and

  (3) megaphylls; megaphylly evolution is summarized by the telom theory
• Monilophytes: Synamorphies of Megaphyllous Plants

  (1) their roots have exarch xylem,

  (2) they have megaphylls, and

  (3) they have a 30 kilobase inversion in the large single-copy region of their plastid DNA.
• Ferns: Intriguing Characters

  • The fern sporophyte consists of a single axis, either a vertical shoots or a horizontal rhizome, that bears both true roots and megaphyllous leaves.

  • The vascular system of the stem is an endarch siphonostele, a derived trait also present in equisetophytes and seed plants.

  • At each node, a leaf trace diverges from the siphonostele, leaving a small segment of the vascular cylinder as just parenchyma; this region is a leaf gap.

  • A vascular cambium has been reported to occur in one fern, Botrychium.
• Seed Plants: Spermatophytes

  • Wood
  • Seeds
  • Gymnosperms
  • Angiosperms
• Coniferophyta

  • Dioecious
  • Small to large, evergreen trees
  • Distributed in both tropical and temperate regions
  • Pine cones as reproductive parts
• Conifers: Pinaceae

  • Pine trees
  • Cedars, firs, spruces, hemlocks, larches
  • Needle-like leaves
• Conifers: Araucariaceae

  • Evergreen trees
  • Spirally arranged, narrow or broad leaves often with parallel veins.
  • Agathis, Araucaria and Wollemia
• Conifers: Podocarpaceae

  • Evergreen trees and shrubs
  • Most diverse group among conifers
  • 19 genera
  • 7 genera in the Philippines
• Podocarpaceae

  • Podocarpus ramosii Mill
  • Podocarpus pilgeri Foxworthy
  • Podocarpus glaucus Foxworthy
  • Podocarpus lophatus de Laubenfels
  • Podocarpus palawanensis de Laubenfels & Silba
  • Podocarpus costalis Presl
  • Podocarpus neriifolius D.Don ex Lamb.
  • Podocarpus rumphii Blume
  • Podocarpus macrocarpus de Laubenfels
  • Podocarpus polystchyus R.Br. ex Endl.
• Conifers: Cupressaceae

  • Cypress family

  • Shrubs to large trees

  • Monoecious or Subdioecious

  • Thuja is commonly cultivated in the philipines.

  • Redwood (Sequoia)
• Conifers: Taxaceae

  • Yew family

  • Small trees and shrubs

  • Spirally-arranged leaves

  • Taxus wallichiana in the Philippines
• Gnetophyta

  • Gnetum (Gnetaceae)

  • Welwitschia (Welwitschiaceae)

  • Ephedra (Ephedraceae)

  • Members have vessel elements

  • Closely related to Angiosperms