04 PLAN OF THE FLOWER, ^LESSON 13. 



section made across the bud) of the Flax blossom, the example of a 

 pattern symmetrical flower taken at the beginning of this Lesson, 

 with its parts all in fm's. 



248. Knowing in this way just the position which each organ 

 should occupy in the flower it is readily understood that flowers 

 often become unsym metrical through the loss of some parts, which 



belong to the plan, but are obliterated 

 or left out in the execution. For ex 

 ample, in the Larkspur (Fig. 183, 

 184), as there are five sepals, there 

 should be five petals likewise. We 

 find only four ; but the vacant place 

 where the fifth belongs is plainly rec- 

 ognized at the lower side of the flower. 

 Also the similar plan of the Monkshood (Fig. 18G) equally calls for 

 five petals ; but three of them are entirely obliterated, and the two 

 that remain are reduced to slender bodies, which look as unlike or- 

 dinary petals as can well be imagined. Yet their position, answer- 

 ing to the intervals between the upper sepals and the side ones, 

 reveals their true nature. All this may perhaps be more plainly 

 shown by corresponding diagrams of the calyx and corolla of the 

 Larkspur and Monkshood (Fig. 192, 193), in which the places of 

 the missing petals are indicated by faint dotted lines. The oblitera- 

 tion of stamens is a still more common case. For example, the 

 Snapdragon, Foxglove, Gerardia, and almost all flowers of the 

 large Figwort family they belong to, have the parts of the calyx 

 and corolla five each, but only four stamens (Fig. 194); the place 

 on the upper side of the flower where the fifth stamen belongs is 

 vacant. That there is in such cases a real obliteration of the miss- 

 ing part is shown by the 



249. Abortive Organs, or veetiges which are sometimes met with ; 

 bodies which stand in tlie place of an organ, and represent it, 



although wholly incapable of fulfilling its office. Thus, in the Fig- 

 wort family, the fifth stamen, which is altogether missing in Gerardia 

 (Fig. 194) and most others, appears in the Figwort as a little scale, 

 and in Pentstemon (Fig. 19f>) and Turtlehead as a sort of filament 

 without any anther ; a thing of no use whatever to the plant, but 



FIG. 192. Piapram of the calyx and corolla of a Larkspur. 10H. Similar diapram ol 

 MonkslKHxl. The <lo*- J i:< cs slu.w whore tho petals are wanting ; one in the former. thre 

 iu the latter. 



