Taxonomy
of Flowering Plants - LECTURE
NOTES - Spring, 1998
Hugh
D. Wilson - rm. 306,
Butler Hall
23 March 1998
The Rosidae
Family Overview - The Rosales
Rosaceae - the Rose Family
Diversity: Herbs, shrubs,
and trees in about 100 genera and over 3,000 species with highest diversity
in northern, temperate parts of the world Important commercially
as a source of ornamentals (Rosa), and various domesticated fruit crops
that are mostly of Eurasian origin [apples (Malus), pears
(Pyrus), cherry, peach, almond (Prunus),
strawberry (Fragaria) and blackberry, raspberry (Rubus)].
Distribution: Worldwide,
but mostly in the northern hemisphere. We have 21 genera with 82
species in Texas, including many common, conspicuous, and early-blooming
inhabitants of the local flora.
Floral structure:
Significant features:
Leaves of varying type but often alternate with stipules.
Flowers with a distinctive suite of features in the androperianth
that is carried by most genera: pentamerous perianth, numerous
stamens, and a hypanthium. Variation
at the subfamily level is based on the gynoecium, as indicated above.
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Physocarpus opulifolius
(Spiraeoideae) -
perigynous flowers at anthesis (left) and in fruit (right - follicle)
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Rubus trivalis (local dewberry)
(Rosoideae)
- flower at anthesis (left) and in aggregate fruit (right) and
domesticated red raspberry with calyx, receptacle, and aggregated
druplets (far right) |
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Geum canadense (Rosoideae)
- flower at anthesis (left) and in aggregate fruit (right).
True fruit is an achene with a hook
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Prunus (Prunoideae)
- front view of flower at anthesis (1), side view with hypanthium
removed (2 - from UH
Botany), P. mexicana (local species currently in
bloom) gynoecium at anthesis (3) and with ovary fully mature (4 =
'Mexican Plum') to produce a drupe
Pyrus (Maloideae)
- front view of flower at anthesis (1), side view (2) (note
pedicel, position of the ovary,
and calyx). Mature pome of Crataegus
(3 - local hawthorne - note pedicel, ovary, and calyx), and cross section
of Malus (4 - apple) pome with a five loculate ovary separated
from the hypanthium by a dim green
line near the outside edge of the locules - see pome
overview
More information on the Rosaceae
Return to Lecture
Notes, the Botany
201 homepage, or the Rosidae
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