After the summer of the second year of growth the plant produces seeds. One individual can produce 100,000 to 180,000 seeds. These seeds are released in close proximity to the plant and can remain viable for over 100 years. The invasive common mullein prefers dry and sandy soils, but is adaptable to many soil types.
primary porosity. (geology). Natural porosity in petroleum reservoir sands or rocks. 1  Facebook. 2  Twitter.rimary porosity. (geology). Natural porosity in petroleum reservoir sands or rocks. 1  Facebook. 2  Twitter.
Weld porosity is the presence of tiny cavities in a piece of welded metal. Porosity can cause all kinds of problems in your welds, so you want to fix the causes of your porosity before they affect your project. Porosity comes in two varieties. Surface porosity, as youâd guess, occurs on the surface of the metal.