Herbarium

These are liquid-preserved collection of whole specimens or portions of specimens which are permanently stored in individual, sequentially numbered shell vials. 

The U.S. National Herbarium attempts to keep Formalin-fixed portions of most specimens in 70% ethanol, with the exception of Corallines, which are kept in 3-5% Formalin. Most specimens are kept either in cotton-plugged, 4-dram (21 x 70 mm) shell vials stored in half-liter canning jars, or in 20-ml scintillation vials with urea/ poly-seal cone caps, filled with preservative. This collection is referenced from the main collection where either a dummy sheet, or a sheet holding a pressed specimen is annotated to reference the liquid-preserved material. The collection itself is sequentially numbered and is housed in light-proof metal storage cabinets adjacent to the main herbarium. 

Storage of wet material in vials kept in canning jars sealed with silicon rubber gaskets has succeeded in preventing evaporation of the liquid preservative. For several years the Department has been experimenting with the use of scintillation vials with urea/ poly-seal cone caps and is considering this form of storage for the main collection. Monitoring of material in these vials is ongoing. 

These are ermanently mounted, stained sections (cross-sections, longitudinal sections, serial sections, etc. of reproductive structures and/or vegetative anatomical preparations), and either partial or whole specimens (e.g., an entire small epiphytic alga) mounted on microscope slides. 

The US National Herbarium maintains permanently mounted, stained sections (cross-sections, longitudinal sections, serial sections, etc. of reproductive structures and/or vegetative anatomical preparations) and either partial or whole specimens (e.g., an entire small epiphytic alga) mounted on microscope slides. The mounting material used varies, as many slides are sent with accompanying herbarium sheets for accession to the herbarium. Slides prepared at the museum are made using the Karo syrup method as described under Collection and Preservation Techniques for Algae. 

This collection is referenced from the main collection where either a dummy sheet, or a sheet holding a pressed specimen is annotated to reference the slide-mounted material. The collection itself is sequentially numbered and is housed in wooden slide boxes stored in metal cabinets adjacent to the main herbarium. 
 

There are over 11,000 specimens held in boxes in the Bulky Material collection (including the air-dried diatom collection). "Bulky Material" (e.g., very large specimens such as the brown kelps, or calcified articulated and crustose coralline algae, epilithic algae on rocks, etc.) are stored in boxes kept in sequentially numbered trays. This collection is referenced from the main collection where either a dummy sheet, or a sheet holding a pressed specimen is annotated to reference the bulky material. The collection itself is housed adjacent to the algal herbarium in standard herbarium cases. Within the cases, specimens are contained in multiple-sized boxes designed to fit into trays of the same length and width as a standard herbarium sheet. 

Trays are 12 X 16 X 2-1/2 inches high 
Box sizes are: 5-1/4 X 5 X 5 inches high
5-1/4 X 3 X 2-1/2 inches high
3 X 2-1/2 X 2-1/2 inches high