Subkeys and Concatenated Keys

The number of keys in FNA is greater than the 2145 keyed taxa from the table in Taxon List & Counts by Type.  One reason is five taxa have alternate keys:

• Asteraceae:   Synoptic and Artificial Keys
• Brassicaceae:  Flower-Based and Fruit-Based Keys
• Lauraceae:  Flower-Based and Fruit-Based Keys
• Portulacaceae Portulaca:  Flower-Based and Fruit-Based Keys
• Salicaceae Populus:  Flower-Based, Fruit-Based and Leaf-Based Keys

Because the alternate keys add new attributes and new paths through the keys, each key must be handled separately (see Node Structure and Types for the mechanism to choose which alternate key to use and see Node Groups and Relationships for the effect on node numbering).

Adding the six alternate keys, there are 2151 master keys.  Of these, 51 have subkeys, so 2100 don't. Those keyed taxa with subkeys tend to have a lot of subkeys: 427.

[9/20/17 - The great majority of subkeys subdivide a taxon. But the subkey may be for a different taxon at the same level. This type of subkey has to be treated differently depending on whether a multiple-attribute-set connector is involved (see Effect of Single and Multiple Parents on Next-Rank Keys in A Key as a Hierarchy). There are examples of each in the Flora of the Pacific Northwest.  A subkey without a multiple-attribute-set connector is Asteraceae Askellia , which is a subkey of Asteraceae Crepis (see 10/8/17 notes and diagram on Effect of Artificial Keys page). A subkey with a multiple-attribute-set connector is Brassicaceae Arabis, which is a subkey of Brassicaceae Boechera (see 8/13/17 notes).]

Summarizing FNA keys by type:

Keys with no subkeys	2100
Keys with subkeys	51
Subkeys	427
Total keys	2578

My list of taxa with multiple keys, with their alternate keys, master key and subkeys, is here. You can see from this list that the names of the subkeys are either an intermediate rank that has its own subkey or a number or letter.

Some taxon pages have a List of Keys, which contains the master key and subkeys. More commonly, keys for intermediate ranks are included in the list of lower taxa. Some of the intermediate ranks listed by this method are singleton parents (they have only one child), so these are not subkeys.

Concatenated Keys - Numbering of couplets and rows in keys and subkeys start with 1; numbering of couplets and rows in keys was discussed in Couplets, Targets and Rows.  But to create a single key for a key that has subkeys, the master key and all subkeys must be concatenated into one key.  The numbering of couplets and rows in the first subkey must be renumbered to continue where numbering left off in the master key, and likewise as each subkey is added.

As an example, look at the couplet and row numbers shown in the partial paths diagram for Brassicaceae Boechera shown in Couplets, Targets and Rows. This was created from the master key and from the Group 1 subkey; the couplets and rows for the subkey were renumbered to continue on from the numbering in master key.

If keys followed a strict hierarchy, from family to genus. to species. and to subspecies, then numbering in keys could start with 1 for each family. But since that is not the case, keys must be concatenated and renumbered again, in order to form one key starting with 1. In the resulting key, targets no longer need to follow the traditional hierarchy.

Printed keys do not need to used concatenated keys.