206 



FORMS OP POLLEN- GRAINS. 



ruptured extine, and probably also by some of the coverings mentioned 

 by Fritzsche as intervening between it and the intine. It contains in its 

 interior fovilla-granules, and its functions will be particularly noticed 

 under fertilization. The number of pollen-tubes which may be pro-: 

 duced depends on the number of pores. In some pollinia, the number 

 of tubes which are found is enormous. Thus, Amici calculates that 

 the two pollen-masses of Orchis Morio may give out 120,000 tubes. 



427. in Cryptogamic Plants there are certain organs which are sup- 

 posed by some to be equivalent to stamens. On that account they 

 were denominated by Hedwig antheridia, by others pollinaria. They 

 consist of closed sacs of different forms, rounded, ovate, oblong, clavate, 

 flask-like, &c., developed in different parts of the plants, containing a 

 number of corpuscles immersed in a mucilaginous fluid, which at a 

 certain period of growth are discharged through an opening at the sur- 

 face. Sometimes the antheridium is a simple cell, at other times it is 

 composed of a number of cells, as in Hypnum triquetrum (fig. 368, 1). 



It either appears on the surface of the plant, or is concealed within its 

 tissue. Antheridia are sometimes confined to particular parts of the 

 plant, at other times they are more generally diffused. Their contents 

 are small utricles or cellules, varying, like pollen -grains, La the different 



Fig. 368. 1. Antheridium or pollinarium, a, of a moss called Hypnum triquetrum, at the 

 moment when its apex is rupturing to discharge the contents, /. 2. Four utricles of the contents, 

 containing each a phytozoon or moving corpuscle rolled up in a circular manner. 3. Single 

 phytozoon separated. 



Fig. 369. 1. Portion of antheridium or globule of Chara vulgaris. Several septate or par- 

 titioned tubes, t, attached to a utricle or vesicle. A mass of similar utricles, forming the bases 

 of a large number of tubes, fills the cavity of the antheridium. 2. Extremity of one of these 

 tubes, composed of several cellules, in each of which is a phytozoon. One of the phytozoa is 

 represented half detached from the cellule. 3. Extremity of a tube from which the phytozoa 

 have escaped, with the exception of the terminal cellule. 4. One of the phytozoa separated. 



