1839] 



FARMERS' REGISTER 



267 



filiate onee the young ear. Where this is not the 

 case, and also in dicBceous plants, the pollen is ge- 

 nerally conveyed by the wind, or by insects, from 

 one flower to the other. The pollen ol" the pines, 

 moved by winds, may often be seen, rising like a 

 cloud above the forests; the particles thus dis- 

 seminated, fall upon the pistillate flowers, and fer- 

 tilize the germ. A curious fact is stated by an 

 Italian writer, viz: that in places about 40 miles 

 distant, grew two palm trees, the one bearing 

 staminate flowers, the other pistillate ones, and 

 that neither ol' them bore fruit for many years; 

 but in process of time they grew so tall as to tow- 

 er above all the objects near them. The wind 

 thus meeting with no obstruction, wafted the pol- 

 !ent to the pistillate flowers, which to the aston- 

 ishment of all, began to produce fruit. In such 

 monoeceous vines as the cucumber (cucumis sa- 

 tivus,) the pollen is conveyed from flower to flow- 

 er by insects, especially honey-bees. The ob- 

 ject of the bee is in the discovery of honey; and 

 whilst searching for it, it unintentionally covers its 

 body with pollen, which it conveys to the next 

 flower it visits, and brushes ofl' as it acquired it, 

 byrummaijing for honey; so that a part is almost 

 unavoidably deposited upon the stiiima, and i'e- 

 cundation is thus efl^ected. "Nor is this altogether 

 so much a work of random, as it at first appears ; 

 for it has been observed that even insects, which 

 do not upon the whole confine themselves to one 

 species of flower, will yet very often remain du- 

 ring the whole day upon the species they hap- 

 pened first to alight upon in the morning." The 

 The agency of insects in transferring the pollen 

 from one flower to another, should be borne in 

 mind, in cultivating such plants as the cucumber. 

 Where thej"- are raised in a hot-house or in any 

 other position, where insects have not free access 

 to them, the staminate flowers should always be 

 taken ofl', and shaken over the pistillate ones. 



Many aquatic plants, which vegetate for the 

 most part \vholly immersed in water, and often at 

 a considerable depth, gradually begin to elevate 

 theirstems as theseason of flowering advances. At 

 length, they rear their heads above the surface of 

 the water, open their flowers, and so continue un- 

 til fecundation is effected ; after which they again 

 sink down to the bottom, to ripen and sow their 

 seed. The most remarkable example of tliis kind, 

 is that of the valisneria spiralis, a plant which 

 grows in the ponds and ditches of Italy. Loudon 

 gives the following description of this curious 

 plant. "The plant is af the class dicccia, produ- 

 cing its fertile or pistillate flowers upon the extre- 

 mity of a long and slender stalk twisted spirally 

 like a cork-screw; which, uncoiling of its own ac- 

 cord about the time of the opening of the blos- 

 som, elevates the flowers to the surface of the wa- 

 ter, and leav^es them to expand in the open air. 

 The staminate flowers are produced in great 

 abundance, upon short upright stalks, issuing 

 from a different root, from which they detach 

 themselves about the time of the expansion ol 

 the pistillate blossoms, mounting up like air-bub- 

 bles, and suddenly expanding when they reach 

 'he surface, where they float about in great nuai- 

 bers among the pistillate flowers, and often cling 

 to them in clusters, so as to cover them entirely ; 

 thus bringing the stamens and pistils in immedi- 

 ate. contact, and giving the anthers an opportunity 

 of discharging their pollen immediately over the 



stigma. When this operation has been perform- 

 ed, the now uncoiled stalk of the pistillate plant 

 begins again to assume its original spiral form, 

 and gradually sinks down, as it gradually rose, to 

 ripen its fruit at the bottom of the water. In 1819, 

 I gathered these stalks, in the canals near Padua, 

 upwards of ten feet long." 



A knowledge of the true nature of the stamenis 

 and pistils, and also of the parts which they act, 

 in the production and pertection of the seed, will 

 enable us to explain a curious fact, which every 

 farmer must have observed, viz: the crossing of 

 different varieties of a plant when growing nea/ 

 each other. When white corn is planted by the 

 side of yellofv corn, the ear produced will be of a 

 character intermediate between the two. This 

 eff'ect is more remarkable in the case of white- 

 corn and the small blue species, termed chicken 

 corn, when raised side by side. The ear pro- 

 duced in such a situation, will very often have the 

 size of the first, and the color of the second 

 spec'es. This eff'ect arises entirely, from the fall- 

 ing of the pollen of the first upon the pistils of 

 the second. Such an effect as this, we would na- 

 turally expect to occur most frequently in the case 

 of those plants which have their stamens and pis- 

 tils in difl'erent flowers; and such is the fact, aa de- 

 termined by observation. Hence the necessi- 

 ty of planting the different varieties of such plants 

 at some distance from each other, if we wish to 

 keep those varieties separate. 



This eflfect however, is not confined to such 

 plants, nor is it necessarily the result of accident. 

 It can be produced in any plant, by artificially k.- 

 cundating the pistil of one variety with the pollen 

 of another. The following experiment of Mr. 

 Knight maybe mentioned in proof this statement. 

 '' In 1787, a degenerate sort of pea was growing 

 in my garden, which had not recovered its former 

 vigor, even when removed to a better soil. Being 

 thus a good subject of experiment, the stamens of 

 a dozen ol' its flowers were destroyed, whilst the 

 pistils were left uninjured. When the blossoms 

 had attained their mature size, the pollen of a 

 very larire and luxuriant gray pea was introduced 

 into one-half of them, but not in the other. The 

 pods of both grew equally, but the seeds of the 

 half which were unimpregnated, withered away 

 without having augmented beyond the size to 

 which they had attained befi)re the blossom ex- 

 panded. The seeds of the other half were aug- 

 mented and matured jis in ordinary cases; and 

 exhibited no difference- from those of other plants 

 of the same variety ; perhaps because the exter- 

 na! coat of the seed was furnished by the pistillate 

 plant. But when they were made to vegetate in 

 the succeeding sprino", the effect of the experi- 

 ment was obvious. The plants rose with great 

 luxuriance, indica'inir in their stem, leaves, and 

 fruit, the influence of this artificial impregnation; 

 the seeds produced, were of a dark gray-color. 

 By impregnating the flowers of this variety with 

 the pollen of others, the color was again changed, 

 and new varieties obtained, superior in every res- 

 pect to the original, on which the experiment was 

 first made, and attaining, in some cases, to a 

 heisrht of more than twelve leei." 



These are cases ol' hybrid plants, produced from 

 different species of the same genus ; whether hy- 

 brids can be produced from species belonging to 

 different genera, is a matter about which bota- 



