PATTERNS CONSPICUOUS IN NATURE. 409 



3. Rank vegetation. — Light from a shiny leaf, or a leaf in 

 strong light against shadow, occasionally forms the pattern. 



4. Scrub, hedgerows, and ivood margins. — Circular leaves in 

 very strong light against dark shadows often give rise to a 

 pattern which is somewhat like a white centre eye-spot one, 

 but distinction must be made between a pattern consisting of 

 light spots on a dark background and the pattern under con- 

 sideration. The first is common in Nature ; the second requires 

 a light centre, a dull margin, and a background of a different 

 tone. Occasionally this arrangement is to be seen among 

 vegetation, but only isolated examples are to be found. 



.5. Light looods. — Hei-e are sometimes to be seen patterns 

 similar to those described under the previous heading. Where 

 sunlight penetrates through foliage and falls on dark ground 

 or foliage beneath, white spots of light result, and when these 

 happen to fall on dark objects they produce the white centre eye- 

 spot pattern. According to the frequency with which they happen 

 to fall on dark objects is the prevalence of the pattern. When 

 the ground beneath the trees is much broken in tone, several 

 may be seen from a single station. Several conditions are, 

 however, necessary for their production — an uncovered more or 

 less vertical sun, a not completely dense canojDy of foliage, and a 

 broken ground beneath. 



6. Heavy looods. — If the foliage be not too dense the pattern 

 may be produced as described in no. 5. 



7. Sky. — On looking np at the sky through foliage, white 

 spots are to be seen in the inter^'als between the leaves and 

 where there are holes in them. If a white spot happens to be 

 surrounded by a dark shadow or a deep-toned leaf, then a white- 

 centre dark-margin eye-spot results. A small number of these 

 are always to be-seen. It may be pointed out that though man 

 is not accustomed to view foliage in -this way, many animals of 

 low stature and whose eyes are set looking upwards as well as 

 forwards must frequently ta.ke this view, 



8. Water. — Very small pools of Avater when they reflect the 

 sky and when, as is often the case, they are surrounded by a 

 ring of moist and therefore dark-toned ground, have the appear- 

 ance of the eye-spot pattern. Foliage ovei'hanging water or 

 floating upon it also rarely gives rise to the same pattern, the 

 sky reflected from the water forming the white centre and the 

 foliage the dark ring. Drops of water and dew under some 

 conditions of lighting give rise to an abundance of the pattern 

 of a transitory nature. 



9. Flowers. — By far the most common examples in Nature 

 of the eye-spot pattern are to be found in flowers. A dark 

 centre eye-spot is as common as a light centre. There can 

 hardly be a doubt that flowers are purposely conspicuous ; it is 

 therefore noteworthy that their patterns conform to the rules 

 which experiments have decided must be followed in order that 

 a pattern may be conspicuous in Nature. 



