Taxonomy 7 Angiosperms and gymnosperms Flashcards
what kind of plants are gymnosperms
vascular plants and seed plants
What is the most diverse gymnosperm group and how many species do they have
conifers, they have 550 species
What are conifers
what can they never be
trees or shrubs, can never be epiphytes or other growth forms
conifer leaves
simple needles or scales, most perrenial.
are conifers evergreen?
most of them
wood of conifers
consists mostly of tracheids, plus some parenchyma cells in rays and resin ducts
* Sieve cells in the phloem
-no sieve tubes
why are conifers able to maintain water transport over many years?
narrow traicheids mean that when sap freezes, the bubbles left afterward will most likely collapse, allowing water to keep flowing
Conifer needle stomata features
-thick cuticle and sunken stomata,
-Stomata are often occluded by wax tubules
–> lowers transpiration, drought resistance
conifers vs environment
conifers are stress tolerators
what do conifers provide for humans
majority of lumber
what are conifers susceptible to?
bark beetles when stressed
Pine family
how many species
largest family of conifers
200 species
pine family where
Primarily in northern hemisphere
* Dominant vegetation of the boreal forest
* Thrive in mountain forests
junipers, redwoods, are part of the
cypress family
as well as the bald cypress–> wet
wollemia
Araucaria family
Wollemia was only known through fossils, which date back 200 MY
* Small population of trees was found in 1994 in Australia
* Not a real ’pine’
broad leaves with unique venation
only has one existing genus
Ginkgophytes
Ginkgo biloba characteristics
-ginkophyte
-urban parks and along streets
-wood is like that on conifers
-male and female trees
-genus been around for 150 years
-deciduous
Unique among the gymnosperms: vessels
Gnetophytes
Gnetophytes
Welwitschia
ephedra
cam photosynthesis?
Welwitschi
with only 2 leaves * Grows in African deserts, (Namibia) * Some plants are 1,000 years old
* CAM photosynthesis
is a gnetophyte
Angiosperms
-First appeared ~130 million years ago
-Monophyletic
-Only plant group with flowers
-Seeds enclosed in the ovary, not naked as in gymnosperms
-Ovary develops into fruit
Gametophyte generation extremely reduced
-Many mutually beneficial interactions with animals that result in the plants being pollinated or having their seeds distributed
how many species do angiosperms have?
250000 species
Angiosperm double fertilization process
one sperm nucleus fuses w the egg; the second sperm nucleus unites w the 2 polar nuclei to form the triploid(3n) endosperm.
- The endosperm nourishes
the embryo
angiosperms vascular elements
sieve elements and companion cells, vessels
Rose family
*Flowers attract bees; mostly insect pollination
*Many species w. edible fruits (apples, pears, plums, cherries, peaches, raspberries, strawberries, mountain ash)
Lily family
*Part of the monocots, herbaceous
*Large flowers w. parts arranged in threes; insect pollinated *Leaves with parallel veins
*Most species grow from bulbs
*Many beautiful ornamental plants: tulips, lilies
