1. The daisy.—Take up several daisy plants ([Fig. 84]) entire, and wash away the soil from the roots. Notice how the stems—some of which are underground—are connected together. Draw a leaf. What advantage is it to the plant to have leaves of the shape noticed? Cut vertically through the “head,” and notice that what is usually called the “flower” really consists of a large number of small flowers.
Fig. 84.—Daisy. (× ¼.)
The central or disc flowers are tubular. Which disc flowers open first, those near the middle or those nearer the edge of the disc? Pick off a flower and notice the 5-toothed corolla. Tear the corolla down with a needle, and observe the tiny stamens (5) fixed on the corolla-tube. The anthers are joined together. Notice the divided stigma of the pistil. The white and pink ray flowers have strap-shaped corollas. They have no stamens, but each has a pistil like that of a disc flower. What do you think is the object of the ray flowers being so conspicuous? Why do they close over the disc at night?
Notice the large number of green bracts below the disc.
2. The dandelion.—Compare the dandelion ([Fig. 85]). Notice that all the flowers are strap-shaped, like the ray flowers of the daisy. Pull one out, and make out the strap-like corolla, the five stamens with joined anthers, and the double stigma ([Fig. 86], 2). Notice the tuft of fine hairs below the corolla and above the knob-like ovary. The tuft of hairs is the top of the calyx-tube.
When the flowers have been fertilised, the yellow corollas wither, and each calyx-tube elongates until it is about an inch long, the tuft of fine hairs being still at the top (4). Blow a “clock,” and notice how easily the fruits are detached from the disc and how slowly they settle. What advantage is this to the plant?
