128 



THE FLOWER 



(Mountain Laurel), (c) by explosion ; Movement of Stamens and Style, 

 (a) to avoid, (&) to secure self-fertilization ; Protection of Pollen and 

 Honey, (a) against unwelcome visitors, (6) against weather, (1) by shape 

 and position of the flower, (2) by bowing of the flower stem at times. 

 This outline will serve as a working basis, which may be extended to 

 include cases that arise in actual observation. 



TERMINOLOGY OF THE FLOWER 



[Inserted for the use of classes that are to take up the determination of 

 flowering plants. ] 



For the student who is preparing to study Systematic Botany, a 

 knowledge of the descriptive terms applied to the parts of the flower 

 and the inflorescence is indispensable. The relationships of plants 

 are more easily studied in their flowers than in the vegetative parts, 

 because in the flower there are brought together in small compass so 

 many sharply marked and readil}' described characteristics, varying 

 slowly, for the most part, through wide ranges of related plants. 

 Descriptions written to enable one to determine the names of the 

 plants that he collects are accordingh^ based very largely on the 

 flower. ]Many of the more usual terms — not already given — are now 

 to be explained. 



253. Terms relating to the general plan of the flower. Flowers 

 are said to be : — 



Perfect (Jiermaphrodite) when provided with both kinds of essential 

 organs, i.e., with both stamens and pistils. 



Complete, when, besides, the}^ have the two sets of floral envelopes ; 

 namely, calyx and corolla. Such are completely furnished with all 

 that belongs to a flower. 



Regular or actinomorphic, when all the parts of each set are alike in 

 shape and size. Flowers of this type can be divided by at least two 



planes into equal and symmetrical 

 parts. 



Imperfect, or better, unisexual, 

 flowers, in which some flowers lack 

 the stamens, others the pistils. 

 Taking hermaphrodite flowers as 

 the pattern, it is natural to say that 

 the missing organs are suppressed. 

 This expression is justified in the 

 very numerous cases in which the 

 missing parts are abortive, that is, 

 are represented by rudiments or 



vestiges, which serve to exemplify 

 Unisexual flowers of the Castor ,, ", i,i i ^ j. 



Oil plant ;p, pistillate, s,stam- ^he plan, although useless as to 

 inate flowers. office. Unisexual flowers are : — 



