No.423.] NORTHERN POLYPETALOUS FLOWERS. 205 
truncate, wedge-shaped bodies, which serve as honey glands. 
The honey is freely secreted on the outer side near the top, the 
nectariferous portion being orange yellow. The fruit is scarlet. 
I have collected upon the flowers in Maine four Diptera, two 
Coleoptera, and one small bee, 7ZaZictus nelumbonis, which con- 
fines its visits to this flower. Great numbers of the small fly 
Hilara atra revel in the pollen. The single species of Cabomba 
is white with a yellow base, and the northern species of Castalia 
(pond lily) are pure white tinged with pink, or deep pink in a 
variety growing in eastern Massachusetts. In the famous 
Victoria regia of the Amazon the outer petals are white and 
the inner crimson, and in Nymphea cerulea of the Nile the 
flowers are blue. The leaves of several genera are strikingly 
bicolored, being light green above and violet or reddish purple 
below. According to Kerner the anthocyanin, or purple color- 
ing matter on the lower side of the leaf, can arrest the rays of 
light (which would otherwise escape into the water) and change 
them into heat and make them useful to the plant. 
The largest tree flowers known belong to Magnolia. ‘Their 
effect in early spring is grand beyond description, illuminating 
the whole landscape and filling the air with their rich perfume." 
The red flower of M. campbellit of Himalaya is ten to eleven 
inches broad, while 77. macrophylla of the Southern States has 
flowers ten inches in diameter. Of the five species of the 
Magnolia four are white and one greenish yellow. M. macro- 
phylla is white with a purple center, while Zzriedendron tulipi- 
fera, tulip tree, is greenish yellow without and yellow within. 
Magnolia grandiflora is fertilized by rose beetles or Cetoniz. 
At night the white flowers are 5° to 10° C. above the surround- 
ing air, and thus afford warmth as well as ‘food. 
Both the Nymphzeacez and Magnoliacez produce very large 
_and conspicuous flowers, which are pollinated by the smaller 
bees, flies, and beetles. While these splendid showy flowers 
are, no doubt, of benefit for attracting the attention of insects, 
yet it is evident that they could be produced only by large trees 
and vigorous herbaceous plants. The water lilies grow in situa- 
tions where the soil is charged with nitrogenous matter, and the 
framework of the plant requires a minimum of mechanical 
