ORCHIDACEAE ORCHIS FAMILY 



Aside from having some of the most beautiful and 

 highly prized flowers known to man, the Orchis family 

 is commercially important, since it is from the seed pods 

 of two tropical climbing species that vanilla is obtained. 



Forty kinds of Orchids are known to grow wild in 

 Illinois, and several of them were at one time abundant. 

 Now, however, not a single species is common. 



The flower of the Orchid is always in threes. The 3 

 sepals are alike and the 2 lateral petals, always alike, 

 commonly resemble them. The third petal forms the lip 

 and is the most colorful and striking part of the flower. It 

 is always dissimilar, often markedly so, usually larger 

 and saclike, frequently bearded or fringed and fitted with 

 a spur which contains nectar for the attraction of insects. 

 All genera except Cypripedium have a single fertile sta- 

 men which unites with the style to form the column in the 

 axis of the flower, at the base of the lip. The style often 

 terminates in a beak at the base of one anther or between 

 the sacs of two. The stigma is the sticky undersurface of 

 the beak. 



The pollen of most of these plants is peculiarly formed. 

 It consists of 2-8 pear-shaped and usually stalked masses 

 in the 2 cells of each anther. These masses, connected in 

 pairs from cell to cell by elastic threads which at their 

 point of intersection are attached to a sticky disk, are called 

 pollinia. 



The seeds of Orchids are extremely small and have 

 very little reserve food in them. In many species they will 

 not germinate under natural conditions except in the 

 presence of certain kinds of fungi. In other species the 

 seeds will germinate but are unable to develop beyond 

 the seedling stage unless the proper fungus, which is 

 always found in the roots of mature Orchids, is present. 



This dependence upon fungi has made the growing 

 of Orchids from seed a very difficult undertaking. Recent- 

 ly it has been found that in some cases at least the stimulus 

 for development that comes from the fungus can be sup- 

 plied by the use of certain chemicals, such as sugars, 

 and Orchid growers are now substituting this method 

 quite extensively. 



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