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BIOLOGY 3404FEVOLUTION OF PLANTS
Fall 2008
Lecture 19Thursday November 27,
2008Selected Eudicots
Angiosperms
Judd et al. 2002. Plant Systematics, a phylogenetic approach.
Approx. 380 families, 250,000 species
Ceratophyllum
Eudicots
From Judd & Olmstead 2004
Ranunculaceae: early eudicots
• Multiple floral parts (numerous stamens and separate carpels)
Left to right, Ranunculus, Hepatica, Clematis
Fagales: oaks, birches, hazels
• Ectomycorrhizae!The inflorescences of Fagaceae (beeches and oaks, left) and Betulaceae (birches, hazels and alders, right) are catkins
Cactaceae: primitive flowers, highly
advanced vegetative parts
http://www.soul.org/BHC%20Gallery%20all%20files/Cactus-flower.jpg
Asteraceae: highly evolved flowers and
inflorescences The Asteraceae is rich in genera (1300+) and species (21,000+), most living in sunny, warm, and often dry environments. Most are herbaceous, but some are trees!
The “flowers” of dandelions are inflorescences, called “heads”
The fruits of dandelions are carried aloft by plume-like modified calyx
Tendrils, in grape (Vitaceae): modified leaves or stems
Cactaceae: leaves modified as spines and stem as water reservoir
Thistle (Asteraceae) spines are modified leaves
Spines in hawthorns (Crataegus, Rosaceae) are modified branches
Tubers, as in potato (Solanaceae), are modified underground stems
Dwarf mistletoe, a parasitic plant; this is a “hemiparasite” because …
This indian pipe is a holoparasite, on an ectomycorrhizal fungus
Leaves of three, let them be … urushiol in poison ivy causes severe histamine reactions (itching rashes and welts) in sensitive persons
Other secondary compounds, such as mescaline, are psychoactive
Cannabis sativa is used both for hemp fibre and cannabinols
Quinine, an antimalarial drug, comes from Chinchona (Rubiaceae)
Cocaine comes from the coca plant (Erythroxylum)
The heart drug digitoxin comes from the garden foxglove, Digitalis
Many eudicots are important forest trees. Aspens (Populus), seen here, are used for pulp, chipboard and chopsticks. All of our important hardwoods are eudicots (e.g., maple, oak, birch, elm, …) or basal angiosperms (e.g., Liriodendron of the Magnoliaceae, important in the SE U.S.)
Some important eudicot crops• Peas, beans, soybeans, alfalfa, peanuts
(Fabaceae)• Cabbage, broccoli, canola, mustard, turnip, radish (Brassicaceae), beets (Chenopodiaceae)
• Tomatoes, potatoes, eggplant, peppers (Solanaceae), olives (Oleaceae)
• Apple, pear, cherry, plum, strawberry, almond (Rosaceae), citrus (Rutaceae), grapes (Vitaceae)
• Cotton (Malvaceae), hemp (Moraceae)• Coffee (Rubiaceae), tea (Theaceae)• Lettuce, artichoke, sunflower (Asteracae)
Rice (a monocot in Poaceae) is the world’s most important, and perhaps the oldest crop
Peas (Pisum sativum in Fabaceae) were also a very early crop, grown 6,000 BC in Tigris-Euphrates valley (Persia - modern Iraq)
Cabbages (Brassicceae): the one in the centre has “bolted” - flowered
Cotton (Malvaceae)
Four families of root crops in Peru: potatoes (Solanaceae), añu (Tropaeolum, nasturtium family) and ullucu (Basellaceae); not shown is oca (Oxalis tuberosum, Oxalidaceae)
Rosaceae: the ovary is inferior, or below the calyx and corolla
The inferior ovary turns into the familiar rose fruits (including apples)
Vitis (Vitaceae), source of ..
Theobroma cacao (Sterculiaceae) is cauliflorous, and source of …
Coffea arabicum (Rubiaceae): where is it native to?
The sugar beet (Beta vulgaris, Chenopodiaceae) is a northern crop
Quinoa (Chenopodium quinoa, Chenopodiaceae) may become an important crop outside of the alpine tropics, but could also become a major invasive weed
Manioc (also known as cassava or yuca; Manihot esculenta, Euphorbiaceae), like many members of its family, contains poisonous latex (milk), but is an important tropical crop
Importance
• Economic: HUGE! List some of the major eudicot crops. What other products, other than food, do we obtain from eudicots?
• Ecological: HUGE! Eudicot trees form the dominant vegetation over large areas, particularly in the tropics.
• Evolutionary: Hugely successful (>175k species); tremendous diversity and huge impact on evolution of other groups organisms, from microbes to vertebrates; coevolution with pollinators and herbivores; complete genomes known for two model genetics systems: Arabidopsis (Brassicaceae) and Lotus (Fabaceae).