Floral Formulas and Floral Diagrams

Transcription

1 Floral Formulas and Floral Diagrams

2 Floral Formulas Floral formula is a means to represent the structure of a flower using numbers, letters and various symbols. A floral formula is a compact form of summarizing information about the flower and its anatomy

3 Floral Diagrams Floral diagrams are stylized cross sections of flowers that represent the floral whorls as viewed from above. Rather like floral formulas, floral diagrams are used to show symmetry, numbers of parts, the relationships of the parts to one another, and degree of connation and/or adnation. Such diagrams cannot easily show ovary position. 3

4 Floral Formulas Floral formulae were developed in early 19th century and used for the first time on a textbook by to describe characteristics of floral families. Sachs (1873) used them together with floral diagrams, he noted their advantage of being composed of "ordinary typeface". Organogenesis of Flowers (1973) takes advantage of floral formulae and diagrams to describe the ontogeny of 50 plant species (embryonic development).. 4

5 Floral Formulas Modern textbooks use floral formulae as a descriptive. Floral formulas (formulae) are useful tools for remembering characteristics of the various angiosperm families. Their construction requires careful observation of individual flowers and of variation among the flowers of the same or different individuals. 5

6 Floral Formula Symbol 1 The first symbol in a floral formula describes the symmetry of a flower. (*) Radial symmetry Divisible into equal halves by two or more planes of symmetry. (x) Bilateral symmetry Divisible into equal halves by only one plane of symmetry. ($) Asymmetrical Flower lacking a plane of symmetry, neither radial or bilateral. 6

7 Floral symmetry

8 Floral Formula Symbol 2 The second major symbol in the floral formula is the number of sepals, with K representing calyx. Thus, K5 would mean a calyx of five sepals. Floral Formula Symbol 3 The third symbol is the number of petals, with C representing corolla. Thus, C5 means a corolla of 5 petals. 8

9 Floral Formula Symbol 4 The fourth symbol in the floral formula is the number of stamens (androecial items), with A representing androecium. A (the symbol for infinity) indicates numerous stamens and is used when stamens number more than twelve in a flower. A10 would indicate 10 stamens. 9

10 Floral Formula Symbol 5 The fifth symbol in a floral formula indicates the number of carpels, with G representing gynoecium. Thus, G10 would describe a gynoecium of ten carpels. 10

11 Floral Formulas Using the 4 whorls of floral parts as our reference Calyx (sepals) = K Corolla (petals)= C Androecium (stamens) = A Gynoecium (pistils) =G

12 Basic Floral Formula *, K5, C5, A, G10 Radial symmetry= *, 5 sepals in the calyx= K5 5 petals in the corolla =C5 Numerous (12 or more) stamens = A 10 carpels = G10 12

13 Floral Formulas Number of Parts K 5 = calyx of 5 sepals C 6 = corolla of 6 petals A 10 = androecium of 10 stamens G 2 = gynoecium of 2 carpels C 0 = corolla missing A 4[5] = androecium usually of 4 stamens, rarely 5

14 Floral Formulas Symmetry K = calyx actinomorphic (radially) C = corolla actinomorphic Kz = calyx zygomorphic (bilaterally) Cz = corolla zygomorphic

15 Floral Formulas Number of Parts (a little more complicated) A 4+2 = androecium of 6 stamens, 4 in 1 set, 2 in another G 2-3 = gynoecium of 2 or 3 carpel A x = androecium of a low unstable number (about 10-20) stamens G = gynoecium of high unstable number, more than 20 carpels

16 Floral Formulas Fusion of Parts (Connation): is indicated by a circle around the number or the number inside parentheses. The number represents the the parts involved. K 4 = calyx of 4 separate sepals C 3 = corolla of 3 separate petals K (4) = calyx of 4 fused sepals G (2) = gynoecium of 2 fused carpels G 4 = gynoecium of 4 separate carpels

17 Floral Formulas Fusion of Parts (cont.) A 5 G 2 = androecium and gynoecium fused by their upper parts K C A = calyx, corolla, and androecium united into a hypanthium

18 Floral Formulas Ovary Position A line below the carpel number indicates the superior position of the ovary with respect to other floral parts. A line above the carpel number indicates the inferior position of the ovary with respect to other floral parts. G = ovary superior G = ovary inferior; flower epigynous -G- = ovary half-inferior G = ovary either superior or inferior

19 Floral Formulas Given: K 5 Cz 1+(2)+2 A 9+1 G 1

20 Floral Formulas Translation Calyx of 5 separate sepals K 5 Cz 1+(2)+2 A 9 +1 G 1 Corolla zygomorphic (bilaterally symmetrical); of 5 petals, 2 fused together, 2 free and forming a pair, and a 5 th different from the others Androecium of 10 stamens, 9 joined by their filaments, the 10 th free Gynoecium unicarpellate, the ovary superior

21 Interpreting Floral Formulas Practice K (5) Cz (5) A 2 or 2+2 G (2)

22 Interpreting Floral Formulas Practice K 3-5 C 5 A G (5-8)

23 Interpreting Floral Formulas Practice K 4 C 4 A 4+2 G (2)

24 Interpreting Floral Formulas Practice K 4 C 4 A 8 G (4)

25 Interpreting Floral Formulas Practice K (5) C (5) A 5 G (2)

26 Interpreting Floral Formulas Practice K (5) Cz 5 A 2+2 G (2)

27 Writing Floral Formulas Practice Given the following description, write the floral formula: Flowers bilaterally symmetrical 5 fused sepals 5 fused petals 4 stamens, 2 in one set and 2 in another Superior ovary, 2 fused carpels

28 Writing Floral Formulas Practice Given the following description, write the floral formula: 4 sepals 4 petals 8 stamen Calyx, corolla, androecium form a hypanthium Inferior ovary, 4 fused carpels

29 Writing Floral Formulas Practice Given the following description, write the floral formula: 3-5 fused sepals 5 petals More than 20 fused stamens Superior ovary, 5-8 fused carpels

30 Writing Floral Formulas Practice Given the following description, write the floral formula: 5 fused sepals 5 petals 10-many stamens, sometimes 4 Superior ovary, 1 carpel

31 Writing Floral Formulas Practice Given the following description, write the floral formula: 5 fused sepals 5 petals, zygomorphic 10 stamens Superior ovary, 1 carpel

32 Writing Floral Formulas Practice Given the following description, write the floral formula: 4-5 fused sepals 4-5 fused petals, zygomorphic 4 stamens in 2 sets of 2 Hypogenous, 2 fused carpels

33 Floral Diagrams Floral diagrams are stylized cross sections of flowers that represent the floral whorls as viewed from above. Rather like floral formulas, floral diagrams are used to show symmetry, numbers of parts, the relationships of the parts to one another, and degree of connation and/or adnation. Such diagrams cannot easily show ovary position. 33

34 Floral Diagram Symbols I 34

35 Floral Diagram Symbols II 35

36 Sample floral diagrams 36

37 Sample Floral Diagrams Described 37