The substitute for the newly collected specimen when the original type material is missing in a herbarium is entitled as

The correct option is Neotype.

In botanical nomenclature, various types of nomenclatural specimens (known as "types") are designated to serve as the definitive reference point for a particular plant name. Understanding why Neotype is the correct substitute requires looking at the definitions of the different typification terms:

1. Holotype: This is the single specimen or illustration designated by the author as the nomenclatural type at the time of the original publication of the plant's name.
2. Isotype: This is a duplicate specimen of the holotype, collected at the same time, from the same place, and by the same collector as the holotype.
3. Lectotype: This is a specimen or illustration selected from the original material (such as syntypes or duplicates) to serve as the nomenclatural type when no holotype was indicated at the time of publication, or if the original holotype has been lost or destroyed, provided that some of the original collection material still exists.
4. Neotype: This is a specimen or illustration selected to serve as the nomenclatural type when all of the original material on which the description of the new species was based is missing, lost, or destroyed. A newly collected specimen can be designated as a neotype to serve as the active nomenclatural substitute for the taxon.

Therefore, when all original type material is completely missing from a herbarium, a newly collected specimen designated to serve as the substitute is referred to as a Neotype.