Section A. Structure and Specialized Characters:
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.

G. Anther Attachment (Figure 6-7-4)

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.