CHAMBERS'S INFORMATION FOR THE PEOPLE. 



male and female organs, it is not hermaphrodite, 

 as these organs occur in different flowers ; in 

 others, again, the male and female flowers exist 

 only on different plants. Lastly, male, female, and 

 hermaphrodite flowers are sometimes found to- 

 gether, either on the same or on different plants. 

 Sometimes the male or female organs alone, pro- 

 tected by a small scale, constitute the flower ; but 

 in general they are surrounded and protected by 

 the corolla and calyx, which are called the floral 

 envelopes. All these are commonly borne on a 

 stalk called the peduncle (from fes, pedis, afoot), 

 which, expanding at its extremity, forms the re- 

 ceptacle, or torus, upon which the whole of the 



a, a, anthers ; d, filament ; b, stigma, or summit of pistil ; e, style ; 

 c, ovary, or seed-vessel ; f, peduncle ; f, calyx ; A, corolla. 



parts above mentioned are supported. What is 

 called the berry in strawberries is nothing more 

 than the fleshy receptacle bearing the carpels on 

 its surface. 



The calyx (from kalyx, the cup of a flower) is 

 the external leafy envelope surrounding the corolla, 

 and in which the latter rests as in a cup. Some- 

 times it is entire, but more frequently it is divided 

 into segments, called sepals, which are more or 

 less separated from each other. It is most com- 

 monly green, but in some flowers it is coloured. 



The corolla (a little crown) is the conspicuous 

 highly coloured part of the flower or blossom, and 

 consists of several divisions or leafy parts called 

 petals, which are articulated at the base, and con- 

 sequently fall off at the earliest manifestations of 

 maturity or decay. The variety of tints in the 

 flowering part of plants is remarkable. The 

 lower part of the single petal of a corolla is called 

 the claw, and the broad part is called the limb. 

 The corolla is frequently furnished with certain 

 secreting organs, attached to the throat or the base 

 of the petals, called nectaries. In some plants the 

 corolla is absent. 



Stamen (a distaff). Within the beautiful corolla 

 are observed several small filaments, arranged in 

 a circle around the central parts, and bearing on 

 their summit little oblong bodies ; which are usu- 

 ally apparently covered with particles of a fine 

 coloured matter like dust These are the male 

 parts of reproduction, the stamens, which are 

 always next to the petals that is, between their 

 base and the base of the seed-organ, or pistil. 

 The number of stamens in each flower varies from 

 one to twenty, or more. In length they are equal 

 or unequal. In the Crucifera there are four long 

 and two short, and in the foxglove tribe there are 

 generally two long and two short. In position, 

 they may be opposed to the divisions of the petals, 

 or they may alternate with them, which is their 

 normal condition. Sometimes they protrude be- 



74 



yond the corolla, at other times they are wholly 

 included within it. The filament which supports 

 the anther is most commonly straight and filiform. 

 On the summit is that essential part the anther 

 (from antheros, belonging to a flower), which 

 is generally formed of two small membranous 

 sacs, or lobes, attached immediately to each 

 other, or united by an intermediate connecting 

 body. In form, anthers are subject to great 

 variety, and, like the filaments, they sometimes 

 cohere so as to form a sort of tube, as in the 

 Composites. 



The pollen (fine flour) contained in the anthers 

 consists of numerous small bodies, which possess in 

 different plants a very different figure, size, and 

 colour. The number of these in an anther-lobe 

 sometimes amounts to many thousands. In some 

 flowers, the pollen-grains are transparent ; in 

 others, they are of a white, purple, blue, or brown,, 

 and more frequently of a yellow colour ; and they 

 often display exquisite markings on their surface, 

 which enable the pollen of certain orders to be 

 identified under the microscope. When a grain of 

 pollen is dropped into water, it swells, and some- 

 times bursts, emitting a minute quantity of granu- 

 lar matter, called fovilla, which is the portion 

 more essential to fecundation. In orchids and 

 some other plants, the pollen occurs in masses, or 

 Pollinia. 



Pistil (from pistillum, a pestle). The pistil is 

 the more or less filamentary body which in most 

 plants rises from the centre of the flower terminat- 

 ing the axis of growth, and is surrounded by the 

 stamens. The pistil represents the female part of 

 fructification. Its parts are i. The ovary, con- 

 taining ovules or rudimentary seeds ; 2. The style, 

 or filamentous part ; and 3. The stigma, or en- 

 larged club-shaped or cloven part forming the 

 apex. The first and last of these are essential, 

 and always present ; but the intermediate one, the 

 style, is sometimes not developed, as in the poppy 

 and mangosteen. The pistil consists organically 

 of one or more carpels (folded leaves), which may 

 either be syncarpous (united into one) or apocar- 

 pous (separate) ; in the latter case, we have two or 

 more pistils in the flower. 



Having thus briefly described the visible repro- 

 ductive organs, let us now turn to their functional 

 phenomena. When the flower expands, and its 

 essential organs have arrived at maturity, the 

 anther-valves open and emit the pollen-grains ; 

 some of these fall upon the stigma, or terminal 

 point of the pistil, where a peculiar tissue, formed 

 of papillary or hair-like cells, is ready to retain 

 them. A curious phenomenon is now observed. 

 The pollen-grain a single free cell develops one 

 or more tubes from its surface, these being formed 

 by its inner membrane, which thus grows through 

 the outer one. These tubes are destined to reach 

 the ovules at the base of the pistil, and thus to 

 carry down from the pollen-grain the matter or 

 influence necessary for fertilisation. The tube, 

 accordingly, penetrates the soft tissue of the 

 stigma, and passes down the centre of the pistil, 

 where a loose conducting tissue is specially formed 

 to facilitate its progress. In this way the pollen- 

 tube often acquires a length several thousand 

 times greater than that of the pollen-cell whence 

 it was produced, its nourishment being derived 

 from the surrounding tissues which envelop it. 

 Mohl regards the development of this filament or 



