ORCHID FLOWERS 



149 



is a petal-like stamen, which does not produce pollen. In 

 most other orchids there is one good anther. 



301. In orchids the pollen is usually borne in adherent 

 masses, one or two masses occupying each sporangium of 

 the anther, whereas, in most plants the pollen is in separate 

 grains. These pollen-masses are known technically as pollinia. 

 Orchids from the tropics are much grown in choice green- 

 houses. Several species are common 

 in woods and swamps in the northern 

 states and Canada. 



254. Longitudinal sec- 

 tion of thistle head. 



256. Cornflower or bachelor's button, 

 255. Floret of in which the outer florets are large 



thistle. and showy. 



302. Spathe Flowers. In many plants, very simple 

 (often naked) flowers are borne in dense, more or less fleshy 

 . spikes, and the spike is inclosed in or attended by a leaf, 

 sometimes corolla-like, known as a spathe. The spike of 

 flowers is technically known as a spadix. This type of flower 

 is characteristic of the great Arum family, which is chiefly 

 tropical. The commonest wild representatives in the North 

 are Jack-in-the-pulpit or Indian turnip (Fig. 251) and skunk 

 cabbage. In the former the flowers are all diclinous and 

 naked. The pistillate flowers (comprising only a 1-loculed 



