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Rosaceae
Ann Bond
March 15, 2001
Rosaceae Taxonomy
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•
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Class
Subclass
Order
Family
Magnoliopsida
Rosidae
Rosales
Rosaceae
– 4 Subfamilies:
• Spiraeoideae
• Maloideae
• Rosoideae
• Prunoideae
Rosaceae Characteristics
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
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
Spiraeoideae
Spiraeoideae
Spiraeoideae
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 hypanthium
Hypanthium-floral tube formed
from the receptacle
• Androecium: many
• Fruits: Accessory: pome
Spur shoots- a short branch
bearing fruit buds
Maloideae
Maloideae
Maloideae
Maloideae
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: drupes
Stipules- paired appendages
sometimes located at the
base of leaf petiole.
Prunoideae
Prunoideae
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, hip
Stolons-modified, elongated, horizontal
stems that creep along the ground.
They root at the nodes or tip to give
rise to new plants.
Rosoideae
Rosoideae
Rosoideae
Rosoideae
Rosoideae
Rosoideae
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: Maloideae
Fruits: Maloideae*
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: Prunoideae*
Fruits: Prunoideae*
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
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
Fruits: Rosoideae*
The Future of Rosaceae
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.