78 



ANALYTICAL CLASS-BOOK OF BOTANY. 



to be composed of starch and oil Collectively they are 

 named the FOVILLA ; and in them have been discovered 

 rotatory motions of great rapidity, which by some authors 

 are considered similar to those observed in the sporangia 

 of cryptogamie plants. 



432. A parent cell, from a pollen grain of the Melon, 

 is seen at fig. 1 6. It contains four secondary or daughter- 

 cells, each with a nucleus in the centre, showing that the 

 pollen grains follow the common law of cell multiplica- 

 tion (34, at (1) ). The parent cell first divides in two, 

 and then each of the parts subdivides in the same man- 

 ner, thus forming four cells. 



433. Sometimes the pollen grains cohere in clusters, 

 as in the Milk-weed, fig. 19, where the pollen masses are 

 seen arranged in pairs, and adhering to the glandular 

 processes of the pistil. At b is a pair of the masses 

 separated. It is better to examine the flowej itself, 

 which is not only very curious, but common and easily 

 procured. No good student will be satisfied with a pic- 

 ture, who can find and analyze the natural form itself. 



434. The stamens collectively have received the 

 name of ANDRCECIUM; and as it is sometimes necessary 

 to speak of the staminal System as a whole, the term is 

 a convenient one. 



435. The number of stamens in a flower is designated 

 by prefixing Greek numerals to the word AKDRIA, which 

 signifies stamen, as in the artificial classes of Linnaeus. 

 Thus a flower is 



Monandrous, with one stamen ; 



Diandrous, two stamens ; 



Triandrous, three stamens; 



Tetrandous, four stamens ; 



Pentandrous, Jive stamens ; 



Hexandrous, six stamens ; 



Heptandrous, seven stamens; 



Octandrous, eight stamens ; 



Enneandrous, nine stamens ; 



Decandrous, ten stamens ; 



Dodecandrous, twelve stamens; and 



Polyandrous, more than twelve, or many stamens, 



436. In regard to comparative size, they are 



(1) Didinamous, four stamens, two longer than the 

 others; and 



(2) Tetradinamous, six stamens, four longer than the 

 others. 



437. Some other peculiarities have also been made 

 the basis of names. The stamens are 



Of what composed ? Motions observed. Describe the four Pollen grains 

 what show ? How is the Pollen in the Milk-weed ? Name of the stamens col- 

 lectively. Define a flower by its number of stamens, from one to many. How 

 when the stamens are united by their Filaments describe varieties^-by their 



Monadelphous, united by their filaments in one set ; 



Diadelphous, united by their filaments in two sets ; 



Triadelphous, united by their filaments in three sets ; 



Pentadelphous, united by their filaments in five sets; 



Polyadelphous, united by their filaments in more 

 than five sets; 



Syngenesious, united by their anthers ; 



Monoecious, stamens and pistils, in separate flowers 

 of the same plant ; 



Dioecious, stamens and pistils, in separate flowers of 

 different plants ; 



Polygamous, staminate, pistillate, and perfect flowers 

 intermingled. 



438. The Functions of the Stamens will be considered 

 in connection with the Pistil, from which they cannot 

 well be separated. 



CHAPTER XXVII. 



THE PISTIL. 



439. THE PISTIL is the interior seed-bearing organ, 

 occupying the centre of the flower. It consists of three 

 parts the Ovary, the Style, and the Stigma. 



440. THE OVARY is the expanded and hollow base of 

 the pistil. It contains the OVULES, or rudiments of the 

 seed, and finally becomes the FRUIT. 



441. THE STYLE is the erect column, usually pro- 

 duced from the apex of the ovary, and which, when 

 simple, or consisting of several combined in one, evidently 

 continues and terminates the Axis of Growth. 



442. THE STIGMA is a more or less rounded body, 

 usually standing on the summit of the Style. The Ovary 

 that bears the seed, and the Stigma which assists in its 

 elaboration, are both essential parts, and are never ab- 

 sent ; but the Style is often wanting, and is, therefore, 

 not essential. When the Style is absent, the Stigma is 

 said to be sessile. At fig. 3 a Pistil may be seen, with 

 its ovary, o, seated on the receptacle of the flower, r ; s 

 is the style, and g the stigma. 



443. ELEMENTARY COMPOSITION. 'The ovary and 

 style are composed of one or more bundles of ducts, en- 

 veloped in parenchyma. The stigma consists of a loose 

 cellular substance called the CONDUCTING TISSUE, and 

 communicates with the ovary by a tube through the 

 centre of the style, as you may see in figs. 12 and 13. 

 The stigma, you will remember (77), is the only part of 



anthers. When are flowers Monoecious Dicecious Polygamous ? 



General subject Define Pistil where situated its parts. Define each. 

 Which essential^not essential ? When the Style is net present how is the 

 Stifcma ? Elementary Composition. What part destitute of epidermis ? 



