380 THE HIGHER DICOTYLEDONS. 



23. How are all Scrophulariaceae distinguished from all Labiates ? 

 Which plants of both families might at first sight be confused, and 

 how could you tell, from the flower, which family a plant with a two- 

 lipped gamopetalous corolla and four stamens belonged to ? 



24. Mention Scrophulariaceae which are pollinated by (a) flies, 

 (6) short-tongued bees, (c) humble-bees, (d) wasps. 



25. Describe the life-history of a single Figwort flower, from the 

 time when its corolla opens. 



26. In what habitats would you look for Mullein, Ivy-leaved Toad- 

 flax, Brooklime, Cow-wheat, Lousewort, Bartsia, Yellow Rattle ? 



27. Describe the flower of Potato and its method of pollination. 



28. Describe the Bittersweet (stem, leaves, flowers, fruit). Where 

 does this plant usually grow ? 



29. Describe the flower of the Tobacco-plant and its mode of 

 pollination. 



30. How is the Potato family distinguished from (a) the Foxglove 

 family, (6) the Borage family ? Mention plants belonging to these 

 families which show some resemblances in general flower-structure. 



31. Describe the fruits of a few Solanaceae, British and cultivated. 



32. Describe the inflorescence and flower of the Honeysuckle, giving 

 an account of the biology of the flower and its mode of pollination. 



33. Describe the vegetative organs (root, stem, leaves) of a Dande- 

 lion. Why is this plant a troublesome weed in lawns ? 



34. Describe the arrangement and shape of the leaves of a Dandelion. 

 What differences in the leaves have you noticed in plants growing in 

 diverse habitats, and how may these differences be explained ? 



35. Describe the structure of the flower-head of a Dandelion. Why 

 is it wrong to call the head a flower ? 



36. Describe the structure of a single Dandelion flower, and relate 

 any observations and experiments you have made on its biology, stage 

 by stage. 



37. Give a general account of the life history of a Dandelion flower- 

 head as seen by watching the same plant day by day from the time it 

 is first visible. How often did the head open and close? For how 

 long did it remain open during a single day ? Did it open every day 

 if not, on what sort of day did it (a) open, (b) remain closed ? 



