The first column is very simply Serial Numbers ... broken into two a) and b)
Notice that keys (descriptions) in 2nd column, written against every serial number are quite distinct (as much as opposite in nature ... for example: a) spines present ... b) spines absent).
The 3rd column is the decisive coulmn.
Based on the description that is true for the plant whose ID is sought, the contents of 3rd column will guide us where to go next.
Thus, let us take a case:
1a Perfect stamens less than 5, or if 5 not all equal (2)
1b. Perfect stamens 5, all equal (5)
Suppose the flower of our plant has Perfect stamens 5, all equal, then (5)
Thus go to serial no. 5 ... forget all the other serial numbers 2 to 4
5a Fruit fleshy when mature, not splitting to dehisce(6)
5b Fruit a dry capsule, splitting to dehisce(15)
Now, suppose the fruit of our plant splits to dehisce, then jump directly to serial no. 15.
15a Capsule circumscissile (opening through a lid. (16)
15bCapsule opening lengthwise or bursting irregularly. (17)
Here if 15b is true, jump to 17
17a Fruiting calyx reflexed, much shorter than capsule.(18)
17b. Fruiting calyx not reflexed, nearly covering the fruit. 17. Nicotiana
If 17b is true, the ID of our plant resolves to Nicotiana genus.
Dr. Gurcharan Singh
Retired Associate Professor
SGTB Khalsa College, University of Delhi, Delhi-110007
Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018.
Phone: 011-25518297 Mob: 9810359089