Ch. 23 Flashcards
The angiosperms are named for having ___.
Flowers
Other important derived characters are numerous methods of ________ that result in the plants being pollinated or having their seeds distributed.
Mutually beneficial interactions with animals
The most obvious alteration was the conversion of gymnospermous sporophylls into stamens and carpels, resulting in the ___.
Formation of flowers
In the transition from gymnosperms to angiosperms, fertilization evolved such that the second sperm cell of the pollen tube fuses with the polar nuclei of the megagametophyte, producing the endosperm nucleus. This is called ___.
Double fertilization
In the last century, wind-pollinated trees were grouped together in a “subclass ___” and were considered the most relictual living flowering plants
Hamamelidae
Wind-pollinated trees
Alders, elms, oaks, and plane trees
Recent DNA studies indicate that this syndrome of large, wind-pollinated trees is a derived condition within ____.
Angiosperms
Approximately 100 years ago, C. E. Bessey developed the hypothesis of the ranalean flower, in which..
A magnolia-type flower was thought to be relictual
Most botanists had long ago concludes that angiosperms are ___, and this is confirmed through recent DNA studies
Monophyletic
Currently, many paleobotanists and taxonomists believe that the transition from gymnospermous to angiosperm occurred during the..
Jurassic and lower Cretaceous periods of the Mesozoic era
Soon after their origin, flowering plants began to follow two distinct lines of evolution, and currently, almost all angiosperms are classified as ___ or ___.
Monocots or eudicots
In general, ___ have only one cotyledon on each embryo
Monocots
Monocots usually have ___ veins because the leaves are elongate and strap shaped
Parallel
___ are distributed throughout the stem in monocots
Vascular bundles
No ordinary ___ in monocots
Secondary growth
Monocots have flowers with parts arranged in groups of ___
Three
Eudicots have ___ cotyledons
Two
Eudicots have ___ venation in the leaves
Reticulate
Their vascular bundles forming one ___ in the stem
Ring
___ can be woody, herbaceous, or succulent
Eudicots
Eudicot flowers parts occur in sets of ___ or ___
Four or five
The monocot/eudicot divergence did not occur right away; the early angiosperms diverged into several clades now called the ___
Basal angiosperms
The three groups of extant descendants of these clades, ___, ___, and ___, have not remained static evolutionary and have not preserved all ancestral features intact.
Amborellaceae, Nymphaeaceae, and Austrobaileyales
We assume that features present in basal angiosperms and gymnosperms are relictual features, ___.
Plesiomorphies
In the most relictual members of ___, flowers are large and showy, with three sepals and three petals, but in others, they are highly modified.
Alismatales
Monocots: Liliales
- one of the largest families
- presence of spots or lines on the petals and of rather ordinary nectaries formed at the bases of tepals or stamens
- many ornamental plants, mostly bulbs
- “typical” monocots
- most unusual is Smilacaceae, with single genus Smilax (catbrier)
Monocots: Asparagales
- septa and septal nectaries in the carpels
- ranging from small, delicate bulbs like Hyancinth, chives, and onion (Allium) to vining epiphytes such as many orchids
- agaves and yuccas
- iris
Agaves and yuccas have ___, ___ ___ leaves.
Giant, fibrous perennial
Some members of ___ and ___ have anomalous cambia and grow to be large highly branched trees.
Agavaceae and Ruscaceae
