CHAPTER XII. 



MONOCOTYLEDONS. 



305. Crocus. The life-history of the Crocus should be 

 carefully studied by continuous observation, according to the 

 following detailed instructions. 



Note that a dry resting-corm is almost entirely covered 

 by brown scales, thin and dry. What can you see of the 

 structure of the scales ? Pull off a bit of this scaly covering : 

 which surface (outer or inner) is rough and dull, and which 

 is smooth and shiny ? In which direction can the scales be 

 torn easily, and why ? Do the strings or fibres, of which the 

 scales are almost entirely made up, run parallel, or do they 

 diverge and form a network, or do they show both of these 

 arrangements? What do you think the strings are, or at 

 any rate were at one time ? 



Now look at the flat or concave lower end of the " bulb " 

 (how can you tell which is the lower end ?) and notice the 

 roughly circular patch. Unless you have examined Crocuses 

 after they have been dug up when the growth of flowers and 

 leaves had finished for the season, you cannot tell how this 

 patch was formed. What can you see on the lower end of 

 the " bulb," just outside of this patch ? Sometimes one can 

 plainly see numerous short slender white pointed projections 

 in this part, arranged in a ring. If you can see these, you 

 should be able to guess that they are young roots. 



Now remove the scales carefully one by one, starting from 

 the lowest. Notice that each scale goes right round the 

 " bulb," and that on removing it you can see a brown line 

 where the scale was attached (Fig. 101). What name might 

 be given to each of these lines ? What name is given to the 

 place where a seed breaks from its stalk, or a leaf from the 

 stem ? Would you call the hard white solid mass to which 



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