rosaceae ann bond march 15, 2001. rosaceae taxonomy class magnoliopsida subclass rosidae order...
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Rosaceae Taxonomy
• Class Magnoliopsida• Subclass Rosidae• Order Rosales• Family Rosaceae
– 4 Subfamilies:• Spiraeoideae• Maloideae• Rosoideae• Prunoideae
Floral Formula:
CA5 CO5 A˜ G1 or G˜ or G 5
Leaves: Alternate, simple, or compound
leaves that have paired stipules
Rosaceae Characteristics
Habit: Trees, shrubs and herbs; mainly in the
north temperate zone
Inflorescences: Solitary flowers; can have
racemose and cymose clusters
Rosaceae Characteristics
Spiraeoideae
• Important genera: Spirea (Bridal Wreath)
• Shrubs with white, yellow, pink, or red flower
• Leaves: simple, alternate, short petioles, without stipules
Spiraeoideae
• Infloresences: umbel-like raceme, corymbs, or panicle
• Gynoecium: superior ovary, apocarpous (separate) of 1-8 carpels
• Androecium: many
• Fruits: follicle capsule
Maloideae
• Important genera: Pyrus (pear), Malus (apple), Sorbus (Mt. Ash)
• Small, branching, deciduous shrubs and trees
• Leaves: simple or pinnately compound, toothed, with stipules
Maloideae
• Infloresences: cyme or corymb• Gynoecium: inferior ovary, syncarpous (fused) of
2-5 carpels, ovary adnate to hypanthiumHypanthium-floral tube formed
from the receptacle• Androecium: many• Fruits: Accessory: pomeSpur shoots- a short branch
bearing fruit buds
Prunoideae
• Important genera: Prunus (almond, cherry, nectarine, peach, apricot, and plum)
• Trees and shrubs (generally small); showy white or pink flowers
• Leaves: simple with stipules
Prunoideae
• Infloresences: corymb, umbel, raceme• Gynoecium: superior ovary, 1 pistil,
hypanthium not adnate to ovary• Androecium: many• Fruits: drupesStipules- paired appendages
sometimes located at the base of leaf petiole.
Rosoideae
• Important genera: Rubus (raspberry), Rosa (rose), Potentilla (cinquefoil), Fragaria (strawberry)
• Upright or climbing shrubs, often with thorny stems; stolons or runners in Fragaria
• Leaves: compound(pinnate, palmate, or alternate) with stipules
Rosoideae• Infloresences: solitary, corymb, raceme• Gynoecium: superior ovary, 10 or more pistils
(each pistil becomes a simple fruit)• Androecium: many• Fruits: aggregate accessory: achene, drupe, hipStolons-modified, elongated, horizontal
stems that creep along the ground. They root at the nodes or tip to give rise to new plants.
Fruits of the Rosaceae: General
• Pericarp: the wall of the ovary in fleshy fruits
• The thickness of the pericarp increases just prior to pollination and fertilization
• The pericarp consists of 3 layers:– Exocarp: outer layer of the pericarp– Mesocarp: middle layer; often fleshy– Endocarp: inner layer of pericarp
Fruits: Spiraeoideae
• Usually a follicle (sometimes called a capsule)• Follicle-simple, dry
fruit developed from a single pistil that dehisces along one margin
• Importance-the plants of this subfamily are used as ornamentals
Fruits: Maloideae
• Pome is predominant fruit in this subfamily
• Pome-simple accessory fruit with more than one carpel– There are several seeds
– Accessory fruits are derived from non-ovarian tissue
– Apples, pears, and chokeberries hang from their pediuncle
• Importance- fruits are used for fresh eating, processing, and plants are used as ornamentals
Fruits: Prunoideae
• Drupes are the predominant fruit• Drupe- a stone-fruit
having a hard inner pit that contains one seed and a fleshy outer layer
• Importance: the edible fruits of this subfamily are used for fresh eating and processing
Fruits: Rosoideae
• Achene, hip, and druplets
• Achene-dry one seeded fruit with a firm close fitting wall– Pericarp is free from the seed– Strawberry is considered a aggregate fruit of
achenes.– Each pistil becomes a fruit and the receptacle
swells and surrounds the fruit
Fruits: Rosoideae
• Hip- an aggregation of achenes surrounded by the receptacle plus hypanthium; considered an accessory fruit
• Druplets-a cluster of fruits clearly traceable to separate pistils of the same flower and inserted on a common receptacle– The receptacle swells and surrounds the fruits
• Importance- fruits are eaten fresh and used for pies
References
• Brickell, Christopher and Zuk, Judith. The American Horticultural Society, A-Z Encyclopedia of Garden Plants. DK Publishing: New York, New York. 1997.
• Harris, James G. and Harris, Melinda Woolf. Plant Identification Terminology. Spring Lake Publishing: Spring Lake, Utah. 1997.
• Jones, Samuel and Luchsinger, Arlene. Plant Systematics. McGraw-Hill, Inc: New York, New York. 1985.
• Wood, Marcia. “Strawberry Growers Test Methyl Bromide Alternatives” ARS. Vol 49, No 1, January, 2001.