J^n.E 2o, 1885. 1 



KNOWLEDGE ♦ 



-49 



NIGHT SKY FOR JUNE (Second Map of Paie), 



Showing the heavens as they appear at the following hours : — 



June 18 at lOi o'clock. 

 June 22 at 10 o'clock. 



June 26 at Of o'clock. 

 Jane 30 at 9i o'clock. 



July 3 at 9 J o'clock. 

 July 7 at 9 o'clock. 



charged through porous slits or curiously opening doo»s. 

 In former papers attention has been called to some of 

 those more obvious peculiarities, and it may suffice now to 

 point to azaleas and rhododendrons as well worth examina- 

 tion for pore openings, and the berberries for door ditto. 

 Going to a recently-opened azalea, the stigma is found wet 

 and sticky, quite ready for pollen, but the accompanying 

 anthers are still closed, so that fertilization must come from 

 insect brought grains of another flower. The anthers of a 

 flower that was in bloom some daj's ago show their two 

 terminal pores very plainly open, and the pollen coming 

 out. 



Beginners may be reminded that stamens are the male 



organs of flowering plants, and they consist of two parts : 

 first, the filament ; commonly a simple slender stalk, Vjut 

 sometimes stout, and often ornamented with lateral api)en- 

 dages ; and at the top of these come their anthers, which 

 form the pollen-grains by an internal growth. The pollen- 

 grains are equivalent, as Sachs says, " to the microspores of 

 the higher cryptogams. 



When the pollen is quite ripe it is easily detached, and 

 if all is washed away the character of the cells that consti- 

 tute the anther tissue may be exhibited by carefully 

 opening it in a drop of water on a slide, and putting a 

 cover-glass over it. A half-inch power with first or .second 

 eye-piece will suffice to indicate whether the anther-cells 



