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IX. ANDROECIUM
A. Androecial Parts
- Stamen. Male sporophyll within the flower; floral organ that bears pollen in angiosperms.
- Staminodium. Sterile stamen, may be modified as a nectary or petaloid structure.
- Staminal Disc. A fleshy, elevated cushion formed from coalesced staminodia or nectaries.
B. Androecial Types (Figure 6-7-2)
(Classification based primarily on fusion of parts)
- Apostemonous. With separate stamens.
- Diadelphous. With two groups of stamens connate by their filaments.
- Gynandrial or Gynostemial. With fused stamens and carpels (stigma and style) as in the Orchidaceae.
- Monadelphous. With one group of stamens connate by their filaments.
- Petalostemonous. With filaments fused to corolla, anthers free.
- Polydelphous. With several groups of stamens connate by their filaments.
- Syngenesious. With fused anthers.
C. Stamen Parts
- Anther. Pollen-bearing portion of stamen.
- Filament. Stamen stalk.
D. Stamen Structural Types (Figure 6-7-3)
(Classification based primarily on structure of filament and anther)
Note: In this classification intermediate types of stamens do occur; shapes, apices, and bases of anthers should be described separately and independently of stamen type.
- Appendicular. Typical stamen with a variously-shaped or modified, protruding connective, as in Viola.
- Laminar. Leaf-like stamen without a distinct anther and filament but with embedded or superficial microsporangia, as in Degeneria.
- Petalantherous. With a terminal anther and distinctly petaloid filament, as in Saxifraga.
- Petaloid. Petal-like stamen without distinct anther and filament but with marginal microsporangia, as in Magnolia nitida.
- Filantherous or Typical. Stamen with distinct anther and filament with or without thecal appendages, as in Rhexia or Vaccinium.
E. Anther Parts
- Connective. Filament extension between thecae.
- Locule. Compartment of an anther.
- Pollen Grain. Young male gametophyte.
- Pollen Sac. Male sporangium.
- Theca. One half of anther containing two pollen sacs or male sporangia.
F. Anther Types(Figure 6-7-4)
(Classification based on dehiscence)
- Longitudinal. Dehiscing along long axis of theca.
- Extrorse. Dehiscing longitudinally outward.
- Introrse. Dehiscing longitudinally inward.
- Latrorse. Dehiscing longitudinally and laterally.
- Poricidal. Dehiscing through a pore at apex of theca.
- Transverse. Dehiscing at rightangles to long axis of theca.
- Valvular. Dehiscing through a pore covered by a flap of tissue.
- Basifixed. Anther attached at its base to apex of filament.
- Dorsifixed. Anther attached dorsally and medially to apex of filament.
- Subbasifixed. Anther attached near its base to apex of filament.
- Versatile. Dorsifixed but anther seemingly swinging free on the filament.
H. Pollen
(See palynology in Chapter 8
- Dyads. Grains occurring in clusters of two.
- Filiform. Thread-like.
- Monad. Grains occurring singly.
- Pollinia. Grains occurring in uniform coherent masses.
- Polyad. Grains occurring in groups of more than four.
- Tetrads. Grains occurring in groups of four.
[ PREVIOUS SUBSECTION ]
[ Section A ]
[ Section B ]
[ Section C ]
[ Section D ]
[ NEXT SUBSECTION ]
[ Introduction ]
[ Beginning of Chapter ]
[ System of Characterization ]
[ Character Classification ]
[ Figures ]
[ Phytographic Literature ]
[ QUERY THE CHAPTER ]