Astronomers are not want to utilize relative measures: astronomical units, a measure of apparent brightness magnitude adjusted for distance, serves as an example. If cosmology can advance with such relative units, why not floristic botany?
Introducing the Steyermark
Julian Steyermark (1909-1988) collected over 130,000 numbers of vascular plant specimens, as noted in the Guiness Book of World Records His maximal collection number I found is 132,006 (ref 1). I therefore propose a unit of floristic botany, the Steyermark (StyM), set equal to 132,006 gatherings.
Floristic exploration depends on field work. Voucher specimens are requisite for field work, hence for floristic documentation. Gathering, processing, data entry, labeling and mounting of specimens is work, tedious work. Once prepared, a specimen nowadays needs to be imaged before it is filed. Any given botanist, however equipped and dedicated, contributes a finite number of specimens. Their, and thus my magnitude, are finite.
Two California botanists of note of note are mentioned here: Robert Folger Thorne (1920-2015) collected ca. 63,000 numbers (G. Wallace, pers. comm.). John Thomas Howell (1903-1994) gathered ca. 55,000 numbers.
Accordingly: Thorne =0.477 StyM, while Howell=0.407 StyM. Many active California botanists have reached the 0.10 to 0.12 StyM range. This author is 0.16 StyM, but not likely to graduate beyond 0.2!
We can also set a relative measure of floristic inventory: specimens per unit area (ref 2). For the western U.S.A., let us here take this to be 90% percentile of collection density as determined on a county basis: 5.55 specimens/square kilometer. Given this, only 3,797,482 additional herbarium specimens are needed - ~28 StyM. Presently, the western U.S.A. is at a density equal to much less.
Hay bailing has its value.
References1 1.) Ann. Missouri Bot. Garden 76: 652-790. 1989. Phytoneuron 2014-53: ISSN 2153 733X