Legumes Flashcards
Name the three families within the monophyletic group of legumes.
- Fabaceae
- Mimosaceae
- Ceasalpiniaceae
List the nine defining features/synapomorphies of the legumes.
- Flowers with 1 carpel
- Placentation of ovules is marginal
- Fruit is a legume, dehiscing along 2 sutures and splitting into 2 valves.
- Leaves are compound (but reduced to simple leaves in many Australian species and phyllodes in Acacia)
- Stipules (small basal leaf appendages) present
- Leaves pulvinate (swellings at the bases of leaves and leaflets for orientating the rachis and leaflet in low light/high heat environments).
- Root nodules with N-fixing bacteria
- Physical seed dormancy (mediated by hard seed coat)
- Seeds often arillate to facilitate dispersal.
Name some of the uses of legumes (or some of the reasons that they are important).
- Timber (acacia)
- Food crops (soybeans, peas, beans, licorice, lentils, alfalfa etc.).
- N-fixation
- Important component of tropical/temperate vegetation
- Ecological interactions with herbivores/pollinators.
Although the legumes are often split into 3 families (the fabaceae, mimosaceae and ceasalpiniaceae families), some classifications recognize ONE family. What is this family called and what are the subfamilies that fall within it?
Fabaceae family with subfamilies Faboideae, Mimosoideae and Ceasalpinioideae.
Fabaceae flowers have a characteristic butterfly-like shape. Discuss the 5 petals, including their arrangement. Also note the number of stamens and style(s) present in each flower.
Fabaceae flowers have one standard petal, two wing petals and two keel petals (the keel petals are partially united). Fabaceae flowers have 10 stamens which can be either all free, all fused at their bases, or usually, 9 are fused at their bases and 1 is free.
Fabaceae flowers have one style.
Fabaceae flowers are imbricate (overlapping), with the standard petal outermost.
Discuss the leaves of Fabaceae members.
Leaves are usually compound,
though are sometimes simple in sclerophyll forms, reduced to spines or scales.
Fabaceae members usually only have a tree habit. True or false?
False! Fabaceae members range from trees to shrubs to herbs, climbers or creepers.
Egg and bacon peas (that are red and yellow in colour) are pollinated by which type of insect?
Bees!
How does pollination occur in egg and bacon peas?
The weight of the bee causes the wing and keel petals to droop down and expose the reproductive parts of the flowers. The underside of the bee then comes in contact with the reproductive parts, picking up nectar or pollen along the way!
Red flowers are often pollinated by _______. These flowers often produce a greater amount of ________ to make the visit worthwhile for the vertebrate!
birds, nectar.
Where are the members of the Ceasalpiniaceae family usually found?
In the tropics, especially in Africa and America.
What is the usual habit of Ceasalpiniaceae members?
Tree/shrub.
Discuss Ceasalpiniaceae flowers including number of sepals, petals and stamens. Also mention the arrangement and types of petals.
5 sepals, 5 petals. 1 standard, 2 wing, 2 keel petals.
10 stamens. Imbricate (overlapping) arrangement of petals where the standard petal is INNERMOST.
Where are Mimosaceae members found?
Widespread in the tropics and temperate areas of the southern hemisphere.
What is the habit of Mimosaceae members?
trees, shrubs, herbs.
Discuss the flowers of Mimosaceae.
- 4-5 small sepals
- 4-5 small tepals
- many, many stamens! (variable in number)
- 1 carpel
- actinomorphic
- usually bisexual
- arranged in elongated spikes, racemes or solitary globular heads
- valvate petals (never overlapping/NOT imbricate)
Acacia is the smallest plant genus in Australia. True or false?
False! Acacia is the LARGEST plant genus in Australia!
Name some uses of Acacia.
- gum and seeds for food
- timber
- bark sometimes toxic and can be used for fishing by indigenous Australians
- water (mulga)
- horticulture
- ecological role of N-fixing
What are the two foliage types found in the Acacia genus?
- bipinnate (or pinnate) leaves
- phyllodes (equivalent to the petiole/leaf stalk)
Acacias ALL produce compound leaves when they’re young. True or false?
True!
Phyllodes tend to be more sclerophyllous in Acacia. True or false?
True!
All Acacia species retain compound leaves until maturity. True or false?
False. Some species of Acacia will retain compound leaves until maturity but others transition to producing phyllodes.
How are Acacia flowers arranged?
In globular heads or cylindrical spikes.
Acacias are protogynous. Meaning that a female phase will come before a male phase. List what happens during both of these phases.
During the female phase, the style elongates.
During the male phase, pollen is shed.
