56 



sometimes found in their proper place inside the petal-like 

 sepals. The presence of rudiments is thus seen to be of im- 

 portance, and in doubtful cases a careful comparison of allied 

 plants often helps us to arrive at a decision. 



The student should carefully examine the flowers of the 

 following plants as they may cause some difficulty. They are 

 fairly typical of the flowers of a large number of important 

 plants and a few special terms are necessary for their des- 

 cription. 



wheat, ( a ) Wheat. The flowers are in spikelets, and each spikelet 



contains from 3 5 flowers. Each flower consists of 3 stamens 

 and one pistil with two feathery stigmas, while the perianth is 

 represented by two small hypogynous scales called lodicules. 

 Each flower is enclosed between 2 scaly bracts, the outer of 

 which is the flowering -glume, while the inner and smaller is the 

 palea. Finally outside of all, at the base of the spikelet there 

 are two more dry, scaly bracts, which are called the outer- 

 glumes. 



The flowers of grasses RW! I am boos closely resemble this 

 type. 



Pea - (b) Common Pea, Bean, Butea frondosa, or a Dalbergia. 



The striking peculiarity here is in the corolla, which is 

 called papilionaceous from some supposed resemblance to 

 a butterfly. The two lower anterior petals, which are inside 

 the others, are narrow and fit close together, forming the so- 

 called keel (carina). Outside the keel are two more narrow 

 petals called the wings (alae), one on each side of the keel, 

 while finally, outside the wings, there is a large posterior 

 upper petal called the standard (vexillum). It should also 

 be noted that the filaments of the stamens are more or less 

 united into a tube. 



Pine. (c) Pine (Pinus). The flowers are unisexual. The male 



flower consists of an axis around which are spirally arranged 

 the numerous scale -like stamens, each stamen bearing two 

 pollen-sacs on its under surface. 



The female flower also consists of an axis with numerous 

 spirally-arranged scales which represent the carpels. In the 

 axil of each carpel there are two ovules, lying on another scale 

 called the placental scale. As the fruit ripens, the placental 

 scales become woody and form the familiar Pine cone. In 

 this n ase the flowers are of very simple construction and there 

 is no perianth. Both the stamens and carpels are scale-like, 

 and finally the carpels do not form an enclosed ovary, the 

 ovules merely lying exposed on their upper surfaces. Plants 



