144 THE OPEN BOOK OF NATURE 
To represent the Sub-class Monochlamydesx I have 
obtained some Spotted Persicaria (Polygonum Persi- 
caria) (see Plate 20, c). It belongs to the Natural 
Order Polygonacez. Unless you have very keen 
eyes, you will need a hand magnifier to examine it 
with. Notice the numerous spikes of crowded tiny 
pink flowers. The perianth is cleft into fine 
deeply-cut lobes. There are six stamens. The 
leaves are lanceolate, and they appear to be bruised 
or stained near the centre. One might say that the 
leaves have blotches of deep green or purple on a 
lighter green background. At the points where the 
leaves join the stem you will observe some mem- 
branous stipules, which are stretched across the 
angles made by the petioles with the stem. This 
form of stipule is called an “ ochrea ” (Latin, ochrea = 
a legging). The magnifier shows that the ochres 
of Persicaria are fringed with bristles. This seems 
a small detail to notice, but it is one of many that 
are sometimes of great importance in identifying 
species. The next species in the genus Polygonum, 
the Pale-flowered Persicaria, has similar ochresx, 
but the lower ones are not fringed. The Spotted 
Persicaria is a common weed in cultivated ground 
and waste places, but its commonness does not 
detract from its beauty. You have but to look 
through a magnifier into the heart of its tiny flowers 
to realize how lovely they are. When we are stay- 
ing in the country we often use this plant for table 
decoration ; it is very effective as such. 
The plant we are now to examine is undoubtedly 
a ‘Monocotyledon, and it must belong to the Sub- 
class Petaloidz, for it has beautiful white petals 
