Proteaceae & Casuarinaceae Flashcards
Proteaceae (in the order Proteales) represent an early diverging lineage among the:
eudicots.
Name the three families mentioned in the lecture that are in the order Proteales.
- Platanaceae
- Nelumbonaceae
- Proteaceae
The relationships of the families within the order Proteales were clarified by molecular data in the mid 1990s. Why were the relationships unclear before this time?
The three families spoken about in class (Platanaceae, Nelumbonaceae and Proteaceae) shared a common ancestor well over 100 m.y.a. and therefore look very different. The relationships were therefore unclear using morphological features alone.
Name the habit, habitat and root type of Proteaceae.
- trees or shrubs
- rainforest, sclerophyll heaths, woodland (multiple colonisations of drier habitats)
- often have proteoid roots “cluster roots”
Describe proteoid roots and explain their function.
Proteoid roots contain a section which is highly branched, that greatly increases nutrient absorption. The roots also secrete organic acids (or contain bacteria) that favour the solubilisation of otherwise difficult forms of phosphorus.
Discuss the distribution of Proteaceae and mention its fossil record.
Proteaceae are a Gondwanan group with a long fossil record. They have southern hemisphere distribution with some northern migration over time (occurring as previously separated land masses came in contact with one another).
Name a genus of Proteaceae that is found in the rainforest.
Macadamia.
Name three genera found in the Proteaceae family.
- Grevillea
- Hakea
- Banksia
Lomatia, Orites and Waratah are all genera that have species found mostly in Australia, with some species occurring in South America.
Are the species currently found in Australia more closely related to each other than to the species found in South America? Or did the three genera diverge a long time ago, before fragmentation of Gondwana occurred?
Australian and South American populations diverged roughly 45-60 m.y.a. and were therefore present in Gondwana before fragmentation occurred.
Eidothea, a new genus in the Proteaceae family, was discovered in the 1990s. A second species within this genus was discovered in the early 2000s. A student studying paleobotany made a remarkable discovery. What was it?
Eidothea (found in QLD), contains fruits that are remarkably similar to fruits from the Victorian fossil record that are 15-20 m.y. old. Indicating that Eidothea is from the same lineage.
List the number of tepals, stamens and carpel(s) found in the flowers of Proteaceae. Are the flowers actinomorphic or zygomorphic?
- 4 tepals (segments united or free)
- 4 stamens attached to the tepals (epitepalous, no filaments just anthers)
- gynoecium of one carpel
What special function do styles have in Proteaceae flowers such as Grevillea flowers?
When the flower is young, the anthers shed pollen onto the tip of the stigma. The style unfurls and extends as the flower matures, acting as a pollen presenter for pollinators (which will hopefully come in contact with the presenter as they pollinate the flower). The stigma becomes receptive during its female phase.
Not all Proteaceae flowers are zygomorphic. Name a genera within the Proteaceae family that has species with actinomorphic flowers.
Persoonia (geebungs).
Persoonia (geebungs) has free stamens. True or false?
False. The stamens of Persoonia flowers are epitepalous (united with the tepals) by a short filament.
In Persoonia (geebungs) flowers, do the styles act as pollen presenters?
No.
Which type of insect pollinates Persoonia (geebungs)?
Bees.
The flowers of smoke bushes have a different pollination strategy than that of Grevilleas or geebungs. Explain.
Flies/bees crawl up into the flower in search of nectar which is produced at the base. The style is sensitive and flings up dramatically when the weight of an insect is detected. As the insect and style are pushed upwards and make contact with the anthers, the anthers send out a cloud of pollen.
Name the three main fruit types found in the Proteaceae family.
- follicles (dehiscent fruits that split along one side at maturity)
- drupes (fleshy, sweet fruits that aid dispersal by animals)
- nuts (dry, indehiscent fruits, some of which have hairs that aid wind dispersal).
Fagales, another order within the Eudicots, contains 7 families including Casuarinaceae. What is the main habit and pollination mechanism seen in these families? How far back does their fossil record go?
Mainly trees, mainly wind pollinated.
Fossil record to c. 100 m.y.a.
Name (using common names) a few other families found within the order Fagales.
- Birch
- Beech
- Walnut
Casuarinaceae is a family within the order Fagales. Are the flowers unisexual or bisexual? Found on the same plant or on different plants?
Monoecious or dioecious. (Separate male and female flowers, found either on the same plant or on different plants).
Where in the world were fossils of Casuarinaceae found? How old are they believed to be?
Name precisely what was found in each area and also discuss why fossils may have been found there.
Fossils containing Casuarinaceae pollen were found in Africa. This may be due to travel of the pollen over great distances and does not necessarily mean that Casuarinaceae was growing in Africa may years ago.
Macrofossils of Casuarinaceae were found in South America, indicating that Casuarinaceae did indeed inhabit this area a long time ago (though it does not today).
What is the largest genus (in terms of number of species) found in the order Fagales?
Allocasuarina.
Name three vegetative features of the Casuarinaceae family (relating to the stem and leaves).
- stems jointed
- stems photosynthetic (cladodes)
- leaves reduced to small teeth and nodes
