Mosses and Ferns

 

I         Bryophyta

A              Characteristics

1         Non Vascular-no specialized conducting tissue (xylem and phloem)

2         Transport takes place by diffusion (slow and inefficient)

3         Short-1 to 5 cm

4         Rhizoids (filaments that grow downward) formed

5         No true organs-stemlike structures and leaflike structures are very similar

6         Haploid gametophyte is the dominant generation

7         They need water for fertilization (sperm swim)

      B      Reasons for survival

            1       Better adapted to certain situations

2    Very tough

3    They are pioneers in areas with little/no vegetation

      C       Life cycle of a Moss

            Gametophyte Stage:

               Begins as a protonema®develops into male/female gametophyte®sperms are released from the antheridia®swim to the archegonia®if mature egg is present, fertilization occurs®zygote is formed®develops into…

         Sporophyte Stage

               Grows into a leafy plant®the stalk with a capsule (sporangia) grows out of it®capsule matures®breaks open and spores are released

 

I         Tracheophyta

A       Vascular Spore dispersing plants-require water for sperm

1     Psilopsida

a-                Whisk fern-oldest known vascular plant, grow from south Carolina to Florida, not really a fern (no true roots/leaves).  Body is an underground stem anchored by rhizoids, as the stem grows it splits into 2 branches (the ends form an Y with the capsules-sporangia-at the tips of the Y)

2     Lycopsida

a-      Club Mosses-low herbs, dominated the coal age (as tall as trees), now only 25 cm tall, have true roots/stems/leaves, some are evergreen

3    Sphenopsida

a-      Horse tails-only one genus-equestium (horse), has 20 species, can be 1 meter tall, live in shaded areas near streams/swamps/ponds, have true roots/leaves, stems have silica (scouring rushes), make coal when they decompose

3      Pteropsida-fern, 9000 species, abundant in rainforests, most ferns grow from underground, stem is called the rhizome, fiddle head (tightly coiled frond), the coal are is the carboniferous period

      B            Vascular seed producing plants

   Gymnosperms-oldest living plant on earth is the bristle-cone pine tree, only grows in California, grown since the Devonian period, second is the Sequoia (100 m). Both are conifers (bear cones-cones grow at the tip of the stem).  Gymnosperm means naked seed, has 4 orders

a.      Cycadales

b.      Ginkoales

c.       Gnetales

d.       Conifers

                                                                           i.      Taxales

 

               A                  Conifers-most abundant and well known, 450 species, grow in any climate, fir/pine/spruce/cedar/redwoods, they are the most economically important tree (80% of our cut lumber)

1                        Taxales-evergreen, used in beds (cheaper than holley), they have no   cones

               B       Cycadales-tropical, second most common order (62 species), look like palm trees, strictly ornamental

               C             Ginkoales-only one species left (maiden hair), has fan shaped leaves, never gets insects on it, originated in China, have no cones, bear fleshy fruit (inedible, smelly, hairy), nothing hurts them (not even gasses), grow slowly, we get medicine from them, they lose one leaf at a time (deciduous)

               D                  Gnetales-two species left, one grows in Utah (Mormon Tea), the other one grows in southwest Africa (Welwitschia) can live for over 100 years, consists of 2 long/flat/leather-like leaves (3 inches or longer)

           

These plants are pioneers in areas with no vegetation, there are 2 kinds of seeds in strobolai (pine cone), the tip of the stem:

1         Ovulate-female cone, produces seeds/eggs, larger cone

2         Staminate-smaller, made of scales on central part of cone

 

Alternation of Generation

                  Gametophyte-meiosis reduces chromosome number®cones and pollen develop (wind is the pollenator)®pollen sticks to the cons®takes all winter to tunnel down to the egg®many fertilized eggs fall to the ground®the strong seeds will survive®the opening to the female cone is the micropyle

 

                       

Angiosperm	Gemnosperm
Flowers	Non-flowering
Covered seeds (pod/fruit)	Naked seed (in cone)
Hard wood (slow grower)	Soft wood (little grain)
Leaves are called leaves	Leaves are called needles
More photosynthetic	Less photosynthetic
Advanced vascular system	Simple vascular system
Deciduous	Evergreen
Less extensive distribution	More extensive distribution

 

 

Conifers give us many different products

Monterey pine (Pinus Radiata)-only grows on eastern slope of the Sierra Navada Mountains of California

Trees that grow in south have wider needles (more sun)

Angiosperms

      Monocot-one seed leaf (cotyledon)

      Dicot-two seed leaves (cotyledons)

            KNOW THE CHART ON PAGE 475

     

 

 

23,600 species of Bryophytes, fragile, decompose quickly so we have few fossils of them, they are considered middle plants (between algae and true plants), sporophyte is non-sexual, among the bryophytes the mosses have the greatest number (live anywhere where there is plentiful moisture), they are held down by rhizoids (roots), they never flower, the spores are diploid, sphagnum moss is the most famous moss (holds lots of water, decomposed into peat moss), the tallest moss is the pigeon wheat (6 cm), Spanish moss is not true moss (part of the pineapple family), ephiphyte can grow on a tree without hurting it.  Liverworts (liver plant) have flat plants, grow horizontally, name is English