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Nonvascular Plants, lacking vascular tissues nonvascular plants are…

- - - - this mucilage attracs Nostoc cyanobacteria - ALL hornworts form this symbiosis and benefit by receiving nitrogen compounds from Nostoc
    - - life cycle of hornworts
      - archegonia do not surround the egg
      - the zygote divides longitudinally yet in mosses and liverworts it divides transversely
- - - - gametophytes are haploid and carry out photosynthesis and collect mineral nutrients
      - gametophytes can spread rapidly through asexual reproduciton
      - sporophytes cannot stand alone because they carry out so little photosynthesis
- - - - Leafy liverworts (orders Jungermanniales and Haplomitiales)
        
        gametophore of leafy liverworts greatly resembles that of a moss - thin leaves on a slender stem but whith two rounded lobes and no midrib
        
        leaves are arranged in three rows
        
        in protrate liverworts where shoot grows flat against the substrate, underside leaves may be suppressed
        
        virtually all liverworts have some or many cells that contain oil bodies
      - thallose liverworts
        
        not leafy, flat and ribbon like
        
        body refferred to as a thallus, a body with no roots stems and leaves
        
        substrate side has unicellular rhizoids and oil drops
        
        side opposite substrate contain chlorophyll and lack oil
        
        cells loosely arranged in aerenchyma, with air pores which do not have guard cells and cannot close
      - gametophores may be bisexual or unisexual
        
        male gametophores of Marchantia produce umbrella shaped outgrowth called antheridiophore
        
        Archegoniophores like their male partners are stalked
        
        archegoniophores and antheridiophores occur on separate plants in marchantia
        
        sperm cells are carried to the archegoniophore by raindrop splashing
        
        sporophytes are so small that each archegoniophore can support many of them
      - sporophyte generation
        
        similar to mosses in basic morphology but structure is distinct #
        
        foot seta and calyptra covered sporangium which is globose and chlorophylous but lacks stomata
        
        liverworts lack a columella no operculum and no peristome teeth
        
        elaters are spring like and help to push spores out
- - - - the leafy stems or gametophores, of many moss plants grow close together tighly appressed forming dense mounds (grimmia, Pholia)
      - in cool wet areas the plants are more open and loose ( Anacolia, Climacium, Platygyrium)
      - Scouleria gametophores grow as ribbons up to 15 cm long submerged in flowing water
      - all moss stems have leaves but not homologous with vascular plants, not coming from the same structures as vascular plant stems and leaves
      - moss gametophores grow from an apical meristem with a prominent apical cell
      - leaves of almost all mosses are only one cell thick except at midrib and margin
      - cuticle occurs only on the upper side and water can be absorbed directly into the lower surface from rain dew and fog
      - stomata do not occur, they would be useless since moss leaves are unistratose
      - stems
        
        always slender and little tissue differentiation
        
        surface layer slightly thicker cell walls and slightly smaller overall, not called epidermis
        
        all stem tissues referred to as cortex
        
        inner cells are larger more parenchymatous and chlorophyllous
        
        there are no stomata
        
        some species stems may have hair
    - - in some mosses, mostly family polytrachaceae, innermost cortex is composed of hydroids that conduct water and minerals
      - leptoid resemble sieve cells having interconnections with adjacent cells acting like companion cells
      - majority of mosses lack hydroids and leptoids, capillary action conducts water along their exterior of the stem
      - in mosses that lack leptoids sugars are moved simply from parenchyma cell to cell
      - rhizoids, while anchored to the substrate, do not absorb water or minerals and lack chloroplasts
    - - growth of the gametophore begins when a spore germinates and sends out a long slender chlorophyllous cell
      - this cell undergoes mitosis and produces a system of similar cells called a protonema
      - this resembles green algae filaments but can be distinguished by the numerous small chloroplasts in each cell, algae having one or two large
    - - gametophore produces gametangia
        
        all mosses are oogamous every species has small biflagellate sperm cells and large nonmotile egg cells
        
        antheridia and archegonia occur on the same gametophore in bisexual species (Funaria, Pottia)
        
        other species have both male and female gametophores (Barbula, Polytrichum)
        
        sperms are produced in microgametangia called antheridia
        
        this consists of a short stalk an outer layer of sterile cells and an inner mass that can differentiate into sperm cells
        
        when sperms are mature antheridium breaks open and releases them
        
        eggs are produced in megametangia called acrchegonia
        
        shaped like a vase with a long neck that is hollow at maturity
        
        release sucrose to attract sperm cells
    - - megagamete and zygote are retained by the gametophyte
      - megagametophytes of vascular plants are small and offer little nourishment or protection to sporophytes
      - however in moss gametophytes are large and photosynthetic and support the sporophyte thoughout its life
      - moss sporophytes never become their own free living plant
      - zygote structure
        
        foot - small bulbous tissue that absorbs sugars minerals and water from the gametophore
        
        capsule - a simple apical sporangium with outer sterile cells and inner cells that differentiate into haploid spores
        
        seta - the narrow stalk between the foot and capsule
        
        sporangium have stomata
        
        operculum - caplike lid
        
        peristome teeth - rows of elaborate teeth that result from cell breakage on the operculum
        
        calyptra - cell layer along the neck
    - - if exposed to dry are these plants dry out
      - many species grow in permanently most habitats
      - some can remain dormant but alive when they get to 30% water weight
      - some mosses can be frozen or taken above 100 C
      - mosses can grow on hard surfaces because they have no roots
      - mosses can make habitats for seedlings
      - in most mosses water is conducted through narrow channels on the outsides of the leaves and stems