ive apparatus. This is especially true of some nettles, and 
particularly of one of their tropical relatives known as the artillery 
plant {Pi lea microphylla ) . In the latter case, if one sprinkles a 
bud-covered plant in the shade with water, and then places it in 
the sunshine, immediately the buds all over the plant explode 
and little clouds of pollen float away. 
Probably the most anciently known example of dioeciousness 
in plants occurs in the date-palm. Possibly even before the historic 
period began, some five thousand years ago, the ancient inhabi- 
tants of the Mesopotamian region recognized the male and female 
trees of this palm and practiced artificial pollination by hanging 
or dusting panicles of the male flowers over the female flower 
clusters, just as they do to-day. On the earthen cylinders and 
tablets from the ancient civilizations of this region, the date-palm 
is depicted as the emblem of fertility, and the act of pollination 
given a religious significance. And even to-day, the Moorish 
Berber, in the sand-surrounded oases of Morocco, mutters an 
Arabic prayer as he performs this act. And of the date palm it 
is said there are over five thousand varieties. What an opportun- 
ity for adaptation — for new combinations better futed to spread 
its kind ! 
In the slow-moving streams and shallow lakes of the northern 
hemisphere grows the eel grass, tape grass, or Vallisneria, a plant 
with the most romantic of all pollination stories. So romantic, that 
Maeterlinck has given a beautiful, fanciful, though essentially 
accurate account of it in “ The Intelligence of the Flowers.” So 
wonderful that even our prosaic botanists forget their usual lan- 
guage in describing it. Both the male and female plants pass 
most of their existence underwater. At flowering time they both 
emerge for a short time. The female plant at this period, by a 
strikingenergy displayed in growth, sends up its bladder-enclosed 
flowers to the surface of the water, where the bladder-like buds 
burst, exposing the tripetailed flower with its densely fringed 
pistils. Herethey float, until pollinated by the little boat-like male 
flowers loaded with a freight of sticky pollen, which throng the 
waters, floating helplessly (I almost said, but hopefully) about, 
waiting to fulfil their mission. In case they do not come in con- 
tact with the female flowers they die and are no more, for they, 
unlike the female flowers, at the time of their maturity beneath 
the waves, break all connection with their parent plant and shoot 
up to the surface. After pollination the female flower “already 
a mother, closes her corolla, in which lives their (the male flowers’) 
last breath, rolls up her spiral (stalk) and descends to the depths, 
there to ripen the fruit of the heroic kiss.” 
In the well-known corn or maize, the male and female flowers 
occur in distinct clusters, but upon the same plant. You know 
them as the tassel and immature ear with its silks. Here, as in 
almost all the grasses, the wind is the great pollinizer. You would 
think that here inbreeding or self-pollination might often be the 
normal thing. But if you planted one stalk or even one row of 
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