Page 168 - Biology_F5

Comparative studies of natural groups of organisms

gynoecium; their numbers; and how they A Represents Androecium or stamens.
relate to each other. Symbols used in The letter A is followed by the number
construction of floral formulae and their of stamens like A (5)+5 that indicates
respective meanings are as summarised a total of ten stamens in which five
below: are free and five are fused. A means

5
Represents radially symmetrical five free stamens. If the stamens are
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flower (actinomorphic). attached to petals, their symbols are
united with an arc line above them as
͡
●|● Represents a flower with bilateral in C A.
symmetry (zygomorphic). ∞ Represents a large and variable
♂ Represents unisexual male or number of whorls. It is used when
staminate flower. the number is more than twelve in a

♀ Represents unisexual female or flower. Example A means many free
∞
pistillate flower. stamens and A (∞) means many fused
stamens.
Represents bisexual (hermaphrodite)
flower. G Denotes Gynoecium or pistil. Each G
is followed by the number of carpels
Br Represents flower with bracts like G or G , which means one carpel
1
2
(Bracteate). and two free carpels respectively. The
Ebr Represents flower without bracts carpels may also be fused, as in G (2)
(ebracteate). or free as in G implying two fused
4
and four free, carpels respectively. A
Brl Represents flower with bracteoles small line under the letter G indicates
(Bracteolate). superior ovary, while a small line

K Represents calyx; each K is followed above it, such as Ḡ, indicates an
by a number indicating the number inferior ovary.
of sepals. For example K represents
5
five free sepals. If this number The following examples highlight how
appears within brackets as in K , it floral formula is constructed and interpreted.
(5)
denotes five fused sepals.

C Represents corolla; each C is followed
by the number indicating number of The above formula indicates that the
petals for example C depicts five flower is radially symmetrical, and it is
5
free petals. If this number is enclosed bisexual. It further implies that the flower
by brackets as in C it denotes five has five sepals, five petals, numerous
fused petals. (5) stamens and five carpels. The flower has

P Is used if sepals and petals are no bracts and all whorls are free from each
replaced by perianth. That is, calyx other that is, they are not fused.
and corolla are fused and cannot be
differentiated.

Form Five Student’s Book
161