In all common Orchids there is only one stamen, which is confluent with the three pistils, to form what is called the column. The edges of the labellum are attached to the sides of the column, leaving a space known as the chamber or mouth of the nectary, and thus the mouth has the column on one side, and the labellum on the other. Although the three pistils are united into one, the three stigmas are not; for the stigma of the upper pistil is transformed into a pouch-shaped viscous mass (_r_, fig. 73), called the rostellum, bearing no resemblance whatever to a stigma, while the other two stigmas form a bi-lobed confluent mass or stigma below it, through which the pollen grains fertilize the ovary, which latter forms the apparently twisted stalk, by which the blossom is attached to the stem. In fact, the rostellum (_r_) projects into the mouth of the nectary, and overhangs the confluent stigmas (_s s_). The lowest and narrowest part of a hood-shaped anther (fig. 73 _a a_,) is attached to the back of the rostellum, and consists of two rather widely separated oblong cells, which open longitudinally in front. Each cell contains a pollen-mass, or pollinium. Fig. 74 represents one with its club-shaped mass of pollen grains, its stalk, and viscid disc. These objects are seen in situ in fig. 73. A pollinium consists of a number of wedge-shaped packets of pollen grains held together by exceedingly elastic fine threads, as in fig. 75; the packets unite into the club-shaped head, and the threads form the stem; the viscid discs are formed by the rostellum. [Illustration: Fig. 74. Pollinium of Orchis mascula:—_p_, pollinium; _c_, caudicle; _d_, disc.] [Illustration: Fig. 75. Pollen grains of Orchis mascula.] At an early period of growth the rostellum consists of a mass of polygonal cells full of brownish matter, which soon resolve themselves into two balls of an extremely viscid semifluid substance void of structure. These two discs are flat on the top, and rounded below. They lie quite free within the rostellum, except at the back, where each viscid disc firmly adheres to a small portion of the exterior membrane of the rostellum. The ends of the two stalks of the pollinia, or granular masses, are strongly attached to these little discs, or balls. [Illustration: Fig. 76. Pollinia of Orchis mascula, showing front view of the discs and caudicles within the rostellum:—_r_, rostellum; _c_, caudicle; _d_, disc.]