Key to Floral Formulas

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Ca = calyx: or whorl of sepals

Co = corolla; or whorl of petals

CaCo = perianth; if sepals and petals are alike termed 'tepals'.

A = Androecium; or whorl of stamens.

G = Gynoecium; or ovary bearing carpels.

X = number of sepals

X = number of petals

X = number of stamens

X = number of carpels: if one, termed 'monocarpous', if two or more and free or distinct, termed 'apocarpous', if two or more and fused, termed 'syncarpous' or connate.

 

X - X = variation in number in that family

 

X = X = Like floral parts in two whorls

= fully fused or connate, especially in reference to the carpels of the gynoecium. If carpel # has no fusion symbol, carpels are free and distinct.

 

= apically fused or connate

= basally fused or connate

= fully distinct or fused; variation within a family

= male unisexual flower

= female unisexual flower

= many

 

* = staminode; a sterile stamen

= adnate; or fusion of two different floral whorls

= 'hypanthium' when all whorls are present. Especially frequent in the Rosidae. The floral whorls are perigynous to the gynoecium, which is still considered superior to them.

= ovary inferior to insertion point of the other whorls. The floral whorls are epigynous to the gynoecium.

= ovary superior to insertion point of other floral whorls. The floral whorls are hypogenous to the gynoecium.

 

= ovary inferior to superior - variation exists within the family; or half inferior.