Lecture 2 Flashcards
What are four major groups of gymnosperms
Gnetophytes, pinales, ginkgoales, cycadales
Name some characteristics of ginkgoaceae family
Only extant species is Gingko biloba
Fan shaped, dichotomously veined leaf
Deciduous
Dioecious
Can live over 1000 years
What are some characteristics of cycadales?
Palmlike
Reproductive structures are in strobili
Specialized root system that houses cyanobacteria –> can fix nitrogen
What is the most diverse group of gymnosperms?
Pinales
Name some families that are part of the gymnosperm group
Araucariaceae (monkey puzzle)
Podocarpaceae: only in Southern Hemisphere
Pinaceae (spruce, fur, pine)
Cuppressaceae (juniper, cedar)
Taxaceae (yew)
What are some common traits of Pinaceae?
Trees and shrubs
Resin canals
Found in Northern Hemisphere
Cones with spirally arranged, flattened bract complexes
Seeds with a long, terminal wing
Are species in the Pinaceae family monoecious or diecious?
Monoecious
What species in the family of Pinaceae have singly attached leaves (that we have seen in the field)?
Picea glauca (white spruce) : needles more triangular than flat, longer needles compared to Picea mariana, blue-ish green needles
Picea mariana (black spruce) : needles dull gray-ish green, straight with white dots
Abies balsamea (balsam fir): leaves a circular scar on twig when needle is detached, flat needles, longer than hemlock
Tsuga canadensis (hemlock): flat 2D needles, 1cm long, shorter needles compared to Abies balsamea, shiny on top, white under leaf
What are some common traits in the Cupressaceae family?
Trees of shrubs
Resin canals
Seeds with pits and ridges
0 or 2-3 short wings
What family is Thuja occidentalis (eastern white cedar) a part of? What are some traits?
Cupressaceae
Folded half small leaves, scale-like foliage
What is the group Sequoioideae?
A subfamily in Cupressaceae of giant trees
Only few species (others extinct)
Very large and long lived, habitats have mild climates (temperature and precipitation)
Within this group we find coast and giant redwoods
What are some common traits in the Taxaceae family?
Taxine (toxic chemical) in all parts except the fleshy aril surrounding the seed
Deer can eat yew, but now cows, sheep, humans, etc.
Important chemotherapy drug
What are the two main groups of seed plants?
Gymnosperms: cycads, gingko, conifers, gnetophytes
Angiosperms: ANA grade, magnoliids, eudicots, monocots
How did carpels evolve?
Evolved from a modified leaf
- modifications of leaf tissues gave rise to the structures in a flower
Ovules (sporangia) became enclosed within a carpel (ovary) that then matured into a fruit
Petals and sepals are modified bracts surrounding the stamens and carpels
What is an example of a way that we have learnt about the history of flowering plants?
Flowers do not fossilize very well. However, fossil pollen has given the first physical evidence of angiosperm emergence.
Pollen has many morphological features and preserves well in the fossil record: very informative for studying ancient plant communities and evolution
What did the earliest flowers look like?
Phylogenetic and fossil evidence suggests that the earliest flowers were small, perfect (male and female in the same flower)
Had radial symmetry
No fusion of parts
Multiple layers of tepals and stamens. Multiple separate carpels, several pistils and separate stamens
What are the 3 orders included in the ANA grade group?
Amborellales, Nymphaeales, Austrobailyales
List some common traits of Amborellales
Only one extant species in the order
Dioecious
Tepals
Numerous stamens
Vessel-less wood
Endemic to New Caledonia
Name some common traits in the Nymphaeaceae family?
Water lily family
All aquatic plants
Large floating leaves with stems attached at the base of the leaf (peltate)
- leaves arising from rhizomes
Style not well differentiated
Flowers with few to many spirally arranged perianth parts and many stamens (petals grading into stamens)
Many fused carpels
What is the Nymphaeaceae flower structure?
Superior, inferior or partly inferior ovary
Laminar placentation
Stamens change from petaloid to normal
Are Lotus a part of the Nymphaeaceae family?
No, they are a part of the Proteales order (monocot group)