NOTES November 30

Euphorbiaceae (Spurge family, Poinsettia family)

• Division Magnoliophyta (flowering plants…= angiosperms)
• Class Magnoliopsida (dicots)
• Subclass Rosidae (includes 18 orders, see p. 203 Walters & Keil)
• Order Euphorbiales
• Herbs, shrubs, vines, trees
• Leaves alternate or opposite
• stems commonly exuding latex
• leaves simple, often palmately lobed
• Flowers tend to be imperfect; thus species are monoecious or dioecious
• Sepals 0-8, petals 0-8
• carpels 3, ovary superior
• styles 3, often forked
• fruits a capsule
• Pan-tropical family, sparingly distributed in temperate regions
• Extremely variable habits, including herbs, woody plants, and "stem-succulents"
• Centers of distribution: South America, Africa

Euphorbia: produces a cyathium as an inflorescence; "false flower" or "pseudanthium, a cup like structure formed of fused bracts, within which are several male flowers, each reduced to a single stamen, and a single female flower, represented by a 3-carleed ovary, on a pedicel. E. pulcherima is the Xmas poinsettia.

Hevea: H. brasiliensis is a tropical S. American tree, source of rubber

Ricinus communis: "castor bean", contains toxins. Source of the toxin "ricin". Castor oil formerly used as a purgative, and as punishment for misbehaving children.

Manihot esculenta: Source of tapioca, and cassava, important as starch sources in Latin America.

Ranunculaceae (Buttercup family)

• Division Magnoliophyta (flowering plants…= angiosperms)
• Class Magnoliopsida (dicots)
• Subclass Magnoliidae (includes 8 orders, see p. 179 Walters & Keil)
• Order Ranunculales
• Herbs, shrubs, vines
• Leaves alternate or opposite or whorled, simple or variously compound
• Flowers perfect, thus the species are synoecious
• Sepals 4-many, often petaloid
• petals 0-4-5
• stamens "many"
• carpels 5-many
• ovaries superior, fruits are achenes or follicles
• "Cosmopolitan", most common in temperate parts of world
• Mostly temperate in distribution
• ancestral flowers are "primitive", featuring many free parts, generally spiraling from base of flower toward apex, radially symmetric
• some flowers more advanced, featuring bilateral symmetry
• many forms of floral/animal interaction for pollination: bees, moths, birds
• Aquilegia ("columbine") has bases of petals specialized into narrow, hollow tubes, containing nectar.
• Clematis: ovaries develop into achenes, with long persisting styles remaining, the style often covered with downy hairs
• Ranunculus (buttercup) has achenes for fruits, often with a hook at the apex…the remains of the style.
• several poisonous species which are problematic to ranchers, poisoning livestock