1. Typification (ICBN Art. 7-10)
Type concept: Each plant name must have a physical representation permanently associated with it (usually a specimen, but note exceptions)
Types are essentially name standards

2. Typification type concept not developed before Rochester Code (1892)
developed and promoted by N.L. Britton (NY) – not adhered to by Europeans at first
N.L. Britton (NY)

3. Note collection number
Ignatz Urban (B)
Erik Ekman

4. Designation of type
Symbolae Antillanae 9(3):

5. Why are types important?
Practical: serve as diagnostic standards of comparison for other specimens
Nomenclatural: provide stability, leading to a regulated and unambiguous nomenclature

6. Types of types
Holotype (HT): the specimen or single element of a collection designated or indicated by the author as the type specimen of a taxon in the protologue.

7. Types of types (cont’d)
Syntype (ST): (1) any of two or more collections cited by author in the protologue when no holotype was designated or (2) any of two or more specimens designated as types.
Example:
“…Follicle cm x 2-3 cm. Seeds obovate, brown, x mm. Ekman 123 (S, NY); Sloane s.n. (BM); Brown (K).”

8. Types of types (cont’d)
Isotype (IT): any duplicate of the holotype (i.e., part of the same collection).
Example 1: Ekman finds a new species of milkweed and collects enough for two sheets. In the protologue of the new species, Urban designates Ekman as the type and deposits it at the Swedish Museum of Natural History (S). He sends the other sheet to the New York Botanical Garden (NY). The material at S and NY are isotypes.
Example 2:

9. Types of types (cont’d)
Lectotype (LT): a specimen selected by a subsequent author from amongst syntypes to serve as the definitive type for a name.
Example:
First Author: “[…] Follicle cm x 2-3 cm. Seeds obovate, brown, x mm. Ekman 123 (S, NY); Sloane s.n. (BM); Brown (K).”
Revisionary Author: “[…] Sloane s.n. (LT: BM!).”

10. Types of types (cont’d)
Neotype (NT): a specimen chosen by a subsequent author to serve as the type, when all original material has been lost or destroyed.

11. Typification issues
Easily applied to newly discovered species, however, the typification of older names often proves problematical for a number of reasons:
unified concept of typification not codified until 1930
the physical destruction of collections (through fire, war, flood, neglect)
the loss of records regarding the location and origin of specimens (through sale, neglect, accident)