REPRODUCTION BY SEED 169 
marigold, rockrose, St. John’s- wort, the sweet-scented 
spirea, broom, and gorse. The first entomophilous 
flowers must all have been pollen-flowers. With the 
arrival of honey, an additional food was offered, and great 
economy was effected in the production of pollen. 
2. Honey-Flowers, which secrete honey or nectar. 
Honey is a fluid rich in sugar secreted by special glands— 
nectaries—which may occur on almost any part of the 
flower. It is usually, however, secreted by a definite 
tissue belonging to the receptacle at the base of the 
ovary—e.g., convolvulus (Fig. 67)—or the stamens— 
Fic. 67.—Convolvulus sepium: Lonet- Fic. 68.— FLowEr oF (Ger- 
TUDINAL SECTION OF FLOWER. anium, WITH SEPALS AND 
a, nectary ; b, superior ovary ; c, style; PetALS Guiana: ore, 
d, stigmas; e, stamens; f, petals; ONEY-GLANDS (q). 
g, sepals ; h, bracts. b, stamens; c, carpels. 
e.g., geranium (Fig. 68). In flowers with inferior ovaries, 
a part of the ovary-wall usually secretes it—e.g., narcissus. 
In other flowers nectaries occur on the petals—e.g., butter- 
cup (Fig. 69) ; the swollen base of the styles—e.g., Umbel- 
liferze (Fig. 70) ; as appendages of the stamens—e.g., violet ; 
or they may be specialized organs which are modified 
stamens or petals—e.g., possibly many of the Ranuncu- 
lace (Figs. 71, 72). It is possible that the secretion of 
honey was first stimulated by the irritation caused by the 
insects biting into the soft tissues at the base of the flower 
for nutritious juices. 
