PRACTICAL WORK. NO. XIV. 227 



are undeveloped and the remaining large ovule is at the 

 end of a twisted stalk. 



V. Sycamore (Acer pseudoplatanus). 



ix. Examine and sketch a half-fruit of Sycamore, 

 noting the wing and the swollen part containing the 

 single seed. 



x. A careful drawing should be made of a trans- 

 verse section of the ovary of the Sycamore, which shows 

 well the two ovules in each loculus, of which one only 

 persists, the other remaining undeveloped. 



VI. Dandelion (Taraxacum dens-leonis). 



xi. Examine a floret from the Dandelion and show 

 on your sketch the pappus representing the calyx. This 

 pappus forms a float, for the purpose of seed distribution 

 by wind. Examine a head of fruits of Tragopogon, which 

 resembles the " clock " of the Dandelion. 



VII. Herb Bennet (Geum urbanum). 



xii. Sketch the fruit of Geum in various stages, 

 showing the persistent calyx, the stigmas and hooks. 

 Make a careful examination with the simple lens of the 

 development of the hooks ; the stigma breaking off at the 

 bend, leaves a hook which serves to distribute the seeds, 

 by becoming attached to animals. 



152 



