106 



Elementary Work in Botany. 



interesting relatives of calla. A plant with a very large 

 purplish-brown spadix and a black-purple spathe is some- 

 times cultivated.* Indeed, there are many kinds of spikes 

 and flower heads besides those of compos- 

 ite flowers proper which appear like sin- 

 gle flowers. Dogwood flowers growing 

 on a flat disk with an involucre of four 

 white bracts; and anemopsis, with its real 

 flowers in a spike all hidden by bracts, 

 very much resemble single flowers. 



Remove the spathe. Find the ring 

 of pistils below the yellow mass of 

 anthers which covers the upper part of 

 the spadix. Is there any nectar ? Cut 

 out a pistillate flower. Do you find 

 any trace of sepals or petals ? Why 

 are these organs useless to a calla? 

 How many carpels make the pistil ? 

 How many ovules are there ? 

 What is the color of the pollen ? What 

 kinds of insects have you seen visiting 

 callas ? 



Draw the spadix; a single pistil magnified, and a cross- 

 section of the stem. Why do not animals eat the leaves ? 



*This plant when ready for the assistance of insects fummons flesh flies by 

 giving out a strong odor exactly like that of decaying meat. Apparently the 

 flies are deceived, and, perhaps, carry pollen without any recompense. 



It would be well to read the story of the cuckoo-pint (or that part of it which 

 tells how flies are imprisoned and made to work for it) from Grant Allen's 

 " Flowers and Their Pedigrees." 



Y 2 

 / 3 



Fig. 82. Anemopsis. A 

 head or short dense spike of 

 apetalous flowers, with white 

 bracts which hide them; the 

 whole surrounded by an in- 

 volucre of petaloid bracts, 

 which makes the head look 

 like a composite flower. 



