Rubbish started to accumulate in the water storage basins, which were invaded by "typha" grass growing several meters high.

Mr. Hassall found that the weight of pollen produced by a single plant of the Bulrush (Typha) was 144 grains.

It is only after a careful examination, that we recognise each of these plants for distinct species,* (* Potamogeton tenuifolium, Chara compressa, Typha tenuifolia.)

We find there, pondweed (potamogeton), chara, and cats'-tail three feet high, which it is difficult not to confound with the Typha angustifolia of our marshes.