80 POPULAR FIELD BOTANY. 
easily distinguished. At night, or under the influence of 
moisture, this brilliant flower closes. In April, May and 
June every grassy bank is adorned with it. 
VERONICA AGRESTIS. Green procumbent Speedwell, and 
Veronica pouita, Grey Speedwell, resemble each other in 
most particulars ; they are as follows; Leaves stalked, egg- 
shaped, deeply serrated. Flower stalks about equal in length 
to the leaves, curved when in fruit. Corolla shorter than 
the calyx. Root small. Seed-vessel of the V. agrestis with 
about six seeds, and the petals pale blue, the lower part 
white; petals of the /. yolita dark blue, many-seeded, and 
the leaves gray, and usually less hairy. 
VERONICA ARVENSIS. Wall Speedwell. Another species. 
with pale blue flowers, but its leaves are heart-shaped, 
broadly serrated, lower ones stalked, upper leaves lance- 
shaped, and not stalked. Stems nearly erect. Corolla 
small, pale blue, with deeper lines, the flowers so arranged 
as to form almost a terminal spike. This is a very common 
species on the tops of walls, in dry fields, and amongst 
rubbish. Flowering late in the month, if the season be mild. 
VERONICA SERPYLLIFOLIA. Smooth or Thyme-leaved 
Speedwell. Clusters rather spiked, flowers of a delicate pale 
blue, reddish-colour before expanding fully, with deep blue 
