Contrad 70, an Effective Softener of Herbarium Material for Anatomical Study

Summary Dried plant material can be prepared for anatomical (or general taxonomic) study by soaking it in a 2% to 5% aqueous solution of Contrad 70 until adequate expansion of the tissue is achieved (this occurring in one to several hours). Advantages of Contrad 70 over Aerosol OT (Ayensu 1967) include: more rapid and effective expansion of tissue, better appearance of sectioned tissue due to removal of slight amounts of obfuscating tannins, and easier microtoming of material due to Contrad's greater softening ability. Contrad has no or very little effect on cutin, starch, crystals, tannins, and secretory compounds.