IN TROD UCTIOJV. 



with perpetual sterility. It is often deeply channelled, or has 

 guiding ridges," .... often approaches the other divisions 

 " closely enough to render the flower tubular." It is properly 

 the upper petal, but a slight twist in the ovary or seed-vessel 

 has turned the flower upside down, a change enabling insects 

 to enter the flower more easily. 



" In most flowers, the stamens, or male organs, surround 

 in a ring the female organs, called the pistils. In all common 

 Orchids there is only one well-developed stamen, which is con- 

 fluent with the pistils and they form together the column. 

 Ordinary stamens consist of a filament or supporting thread 

 (not always seen in the Orchids) which carries the anther" and 

 this is " a sort of case filled with a waxy or meal-like powder, 

 called the pollen, which serves to fertilize the pistil." " The 

 anther is divided into two cells, which are very distinct in 

 most Orchids, and appear in some 

 species like two separate anthers." 

 " Orchids properly have three pistils 

 united together, the upper and anterior 

 surfaces of two of which form the two 

 stigmas. But the two are often com- 

 pletely confluent so as to appear as 

 one." The grains of pollen, when de- 

 posited on the stigma, " emit long 

 tubes," and these penetrating the sur- 

 face, " carry the contents of the grains 

 down to the young seeds in the ovary," 

 which, when mature, is " a i-celled, 

 3-valved pod, with innumerable minute 

 seeds appearing like fine sawdust." 

 " The upper stigma is modified into an 

 extraordinary organ called the 7'ostellum, which in many Or- 

 chids presents no resemblance to a true stigma. When mature, 

 it either includes or is altogether formed of viscid matter." 



Fig. 2.— Section of the Flower 

 of an Orchid. (From Darvvin.) 



Pe, Pe, Petals ; Se, 6V, S>, Sepals ; 

 S, S, Stigmas ; Sr, Stigma mod- 

 ified into the rostellum. 



A, Fertile anther of the outer 

 whorl ; A^ A- 3 , anthers of the 

 same whorl combined with the 

 lower petal, forming the label- 

 lum ; «,, a 2 , rudimentary an- 

 thers of the inner whorl (fertile 

 in Cypripedium), generally 

 forming the clinandrum ; a a , 

 third anther of the same whorl, 

 when present, forming the 

 front of the column. 



