330 FUNARIA. 



pointed tip ; the leaf consists of a central cylindrical 

 midrib and a single-layered wing on either side; the 

 cells of the midrib are long and narrow, those of the wings 

 polygonal. 



Examine carefully the chloroplasts in the cells of the 

 wing look for stages in the multiplication of the chloro- 

 plasts by median constriction and division. Treat a leaf 

 with iodine, and note the small starch-grains inside the 

 chloroplasts. 



469. Sections of Stem and Leaf of Punaria. Hold several 

 stems in pith, and cut transverse and longitudinal sections. Note 

 in the stem (1) the peripheral tissue with brown cell-walls ; 

 (2) the central strand of long narrow colourless cells with thin 

 walls. In T. S. of leaf, note the single-layered wing on either side 

 of the midrib ; in the midrib (1) a sheath of green cells on the sur- 

 face above and below, (2) an inner sheath of narrower cells with 

 thicker walls, (3) a central strand of narrow thin-walled cells. 

 In favourable longitudinal sections of stem, note that the " leaf- 

 races " pass downwards in the outer tissue but do not directly join 

 the central strand of the stem. 



470. Male "Flower"; Antheridia (Fig. 77). Cut 

 off a male shoot, including the star-like male " flower," 

 and tease this out in water so as to isolate the anthe- 

 ridia ; cut longitudinal sections of another flower, held 

 in pith. 



Note (1) the leaves forming a spreading cup around 

 the central portion of the " flower," which consists of 

 (2) antheridia, oblong sacs inserted on a short stalk, the 

 sac having an outer layer of flattened cells containing 

 chloroplasts which later turn red or brown, and a dense 

 central mass of sperm-cells ; (3) the paraphyses, mixed 

 with the antheridia and consisting of a single row of cells 

 the uppermost cells greatly enlarged and containing 

 abundant chloroplasts. 



Antheridia of different ages may be found. Look for 

 the large clear cap- cell which is thrown off when the ripe 

 antheridium dehisces. Some of the antheridia may be 

 empty, having opened to let the antherozoids escape by 

 the pore thus formed at the apex. In examining a ripe 



