The pupil is always dilated and insensitive to light.
In length, with very deep lobes at the lower part, but dilated widely at the apex, and there notched.
Lower part of canal, enlarged; o, cavity of canal, surrounded by a sheath of cells, dilated towards the bottom of canal, in which a large pollen-grain is caught; ex, exterior of pollengrain; in, internal group of prothallial or antheridial cells.
The tubes have their cavity dilated at intervals, and Penhallow has therefore compared them with the trumpet-hyphae of Laminariaceae, but no transverse septa are anywhere visible.
In some instances, as in Tamarix gallica, Peganum Harmala, and Campanula, the base of the filament is much dilated, and ends suddenly in a narrow thread-like portion.