Q. What do you mean by Punch cards?

Punch cards are used when the number of taxa to be keyed out is large. In this type of cards the holes at numbers corresponding to a character are made open by cutting the perforations up to the margin. Each number is allotted to the character. For example, following statement is prepared for the taxa I to IV already discussed in the table.

1. No. of Cotyledons - 1 (one)

2. No. of Cotyledons - 2 (two)

3. Leaves reticulate veined

4. Leaves parallel veined

5. Flowers trirnerous

6. Flowers tetramerous

7. Flowers pentamerous

8. Flowers with sepals and petals

9, Flowers with one type of perianth

10. Flowers with one whorl of perianth

11. Petals free

12. Petals fused connate

When the character is present, the corresponding holes are cut open up to the margin when a poker is inserted in a bunch of cards at that number. Such ca~d8st which the number has been cut open on account of 'the presence of the character fall down and others don't. Thus two groups are made on the basis of this character. All cards belonging to taxa I will fall out, when characters at number 2,3,6,8,10,11 are tried, while those belong to taxa IV will fall out when characters at No. 1, 4,5 and 9 are  attempted.