December 29, 1976: 41 years ago today

What plant is this?  Well, we don’t know exactly.  This undetermined specimen was collected on December 29, 1976 by Jeffrey McElroy in Ecuador.  The label suggests it is in the same plant genus as the papaya (Carica) but was not yet identified to species.  Specimens in the herbarium are arranged by plant family, then genus, then geography (where it was collected), and in nearly every genus, at the bottom of all these folders is a black colored folder labelled “indet.” that includes those specimens that have not yet been identified to species.  I’m not sure why they are called “indet.” rather than “undet.”, as “undetermined” would be more appropriate.  Of the over 525,000 specimens in the Carnegie Museum herbarium, about 2% (= 10,588 specimens), are not (yet) identified to species.
 
This specimen is likely a member of a species already known to science, but an expert has not yet identified this particular specimen yet.  However, many undetermined specimens may be undescribed (that is, new to science!).  The name and description of new species (alpha taxonomy) is a major purpose of herbaria.  A study in 2010 estimated that of the estimated 70,0000 species yet to be described, over HALF are lying in herbaria right now!  They also found that only 16% of new species descriptions were done within 5 years of specimen collection, and 25% of new species descriptions involved specimens that were more than 50 years old!
Study abstract here: http://www.pnas.org/content/107/51/22169.abstract
 
Taxonomy (branch of science on classification of organisms) is always changing.  Species names are changed, what was once thought to be one plant species or family is split into many, and what was thought to several species is lumped into one.  And with further information or upon review by experts in particular plant groups. specimens are determined to be a different species than what the original collector called it.  Annotation labels are added to specimens all the time – these labels revise the species listed on the original label.  A typical annotation label includes the revised species name and details, the name of the person making the annotation, and the date.
 
Some specimens can have many annotations, which nicely demonstrates the community culture of science as a process with constant revision as we learn more about the world around us.