OR, PLAIN TEACHING. 



295 



racemes are erect, at other times 

 they are droop- 

 ing. When 

 the flowers are 



u arranged upon 

 I pedicels of 



various 

 lengths, so as 

 to bring all 

 the blossoms 

 nearly to a 

 level, the 

 stalks of the 

 lower flowers 

 being longer than those of the 

 upper, the group is called a 

 corymb, 15 ; but when the flower- 

 stalks all spring from one point, 

 17, the group of blossoms thus 



15 16 



735. 



formed is called an umbel, 16, and 

 plants exhibiting this peculiarity 

 constitute the order umbelliferce, 

 in the natural system. They 

 constitute one of the least attrac- 

 tive groups of plants, and yet 

 one of the most important to the 

 world. Some of them are useful 

 as food, others dangerous as 

 poisons ; in their native ditches, 

 they are often noxious weeds, 

 but under the influence of culti- 

 vation they lose their venom, and 

 become wholesome. They may 

 generally be recognised by their 

 hollow stems, and cut leaves, the 

 bases of which wrap round the 

 stalks. From these plants we 



derive the parsnip, the carrot, 

 &c, and an examination of the 

 flower-heads of those named will 

 show the true character of the 

 umbels. When flowers are' set 

 upon the stem, the latter con- 

 is 19 20 



736. 



stitutes a spike, 18 ; and in the 

 catkins of the willow, 19, and the 

 heads of grasses, 20, a similar 

 form of inflorescence is called the 

 axis, or rachis. 



These are only a few of the 

 distinctive peculiarities of flowers, 

 and their modes of blossoming. 

 They are so interesting, and offer 

 so much assistance in observing 

 and describing the beauties of 

 plants, and in the study of 

 botany, that we will arrange a 

 table of a greater number of 

 them, giving an illustration of 

 each peculiarity worthy of obser- 

 vation in the structure of any 

 plant, so that the student noticing 

 any of these distinguishing 

 features in a specimen he may 

 find, may at once be able to know 

 how to describe it. The pecu- 

 liarities of leaves having been 

 already illustrated, 569, we omit 

 from the table such forms as, 

 having been already given, can 4 

 with equal facility, be referred 

 to :— 



