A. - Butomus umbellatus, Linnaeus: p. 125.

1. A flower with the perianth removed.

2. One of the carpels.

3. A transverse section of the carpels. B. - Typha latifolia, Linnaeus: p. 121.

1. A male flower, separate.

2. A female flower, separate.

C. - Acorus Calamus, Linnaeus: p. 123.

1. A flower with its green scales and stamens, and broad sessile stigma.

2. One of the scales with its accompanying stamen, separate.

3. An ovary.

D. - Potamogeton natans, Linnaeus: p. 123.

1. One of the flowers.

2. A stamen, separate.

3. One of the carpels.

E. - Lemna trisulca, Linnaeus: p. 122.

1. A frond with its branches and root.

2. A flower.

F. - Juncus efiusus, Linnaeus: p. 124.

1. A portion of the cylindrical stem.

2. A flower.

3. A capsule with the dry persistent perianth. G. - Carex riparia, Curtis: p. 129.

1. A flower of the male spikelet with its glume.

2. A flower of the female spikelet with its glume.

Plate 21.

Butomus umbellatus

Typha latifolia

Acorus Calamus

Poiamogeton nataris

Lemna trisulcas

Juncus effusu

Carex riparia

W Fitch. del. et. bith

Vincent Brooks Lmp