Objects for the Microscope. 13 



in all, you will probably observe a larger granule, with a 

 lesser one within, or perhaps several lesser ones ; the large 

 granule is the nucleus, the minute inner ones the nucleoli ; 

 they are the supposed origin of new cells, and much that is 

 exceedingly interesting has been written in the works before 

 referred to : ' Mohl on the Vegetable Cell ; ' ' Hofineister's 

 Die Enstehung des Embryo.' These nuclei are to be 

 observed in pollen-grains, in the hairs of Tradescantiae, or 

 Spiderwort, especially in the pollen of the fir-tree tribe. 



OIL CELLS. 



Cells containing oil are beautiful objects when found as 

 on rose-trees, on the stem of Saxifrage, Geraniums, Col- 

 lomia, Drasena, raised upon delicate stalks, often brightly 

 coloured, or glittering diamond-like in the sunshine.* Some- 

 times the oil cells are sessile, in golden spots upon the back 

 of a black-currant leaf ; or white and silvery in the recesses 

 of a Sage leaf, a leaf of Rue, or Hop, or Mulberry. 



Sometimes these oil cells are internal, as in the rind of 

 an orange, where they are very large and most easily ob- 

 served ; also in the leaves of Myrtle and Magnolia, of 

 Hypericum, St. John's wort, so common in woods and 

 hedges : those little dark dots are the oil cells, and trans- 

 parent, if you hold the leaf up against the light, and 

 examine it with a pocket lens. 



HAIRS OF PLANTS. 



The hairs of plants will furnish you with abundant ma- 

 terial for study and delight throughout the summer long, 

 and the variety in their form will astonish you. Look at 

 the beautiful bead-like hairs of the Spiderwort a rich 

 purple chain of cells fringing each stamen. White, trans- 

 parent, glittering rows of 5 cells from the flocculent mass of 

 hairs we see on the leaves and stem of the common 

 Groundsel. The common garden Verbena has the mouth 

 of its corolla closed by a dense row of beaded hairs pro- 

 tecting its pistil. I cannot describe more, but look at these. 



* These are called glandular hairs. 



