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).