It may be a modified stoma with the guard cells permanently open so that water is lost passively by hydrostatic pressure, as in sea lavenders (Limonium), or a glandular hair from which water is actively secreted, as in runner bean (Phaseolus).

• 这可能是由于气孔的保卫细胞永久张开而使水分在静水力的作用下被动排出，比如海薰衣草（补血草属）；也可能是由腺毛主动分泌水分到外部，比如红花菜豆（菜豆数）。