H 



ANALYTICAL CLASS-BOOK OF BOTANY. 



its immense leaves, where the pelican and sand-piper! 

 walk, and fish without wetting their feet, and mon.-trous 

 scrpeuts coil themselves amid the rank verdure of those 

 great solitudes, that nurture at the same time the most 

 beautiful and the most terrible forms. 



515. The Evening Primrose begins to unfold its 

 flowers directly after sunset. The leaves of the calyx 

 burst and fly open, with an audible report, emitting at 

 the same time a very agreeable odor. The straw-colored 

 petals unfold themselves more deliberately ; and the 

 flower fades during the next day. The Morning Glory 

 and some of the 1'ortulucca and Cistus tribes open with 

 the early dawn, and close at evening; the Mirabilis 

 generally is out about the middle of the afternoon, 

 whence its common name of Four-o'clock ; while the 

 flower of the Goafs-beard regularly expands in the 

 morning without regard to the weather, and closes about 

 twelve o'clock ; and for this reason is called Go-to-bed- 

 at-noon. Many species of Trefoil in plants of the Clover 

 tribe fold their leaves on the approach of a storm. The 

 Chick-weed (Anagallis) closes its flowers, while the Sow- 

 thistles open theirs on the approach of a storm. Many 

 other instances might be given ; but you will seek them 

 for your own benefit, which will thus be greatly en- 

 hanced. 



516. MOTIOXS CAUSED BY TOUCH. One of thejnost 

 remarkable instances of this kind is the Sensitive Plant 

 (Mimosa), which is represented in fig. 3. If one of the 

 leaflets be touched, it seems to shrink from the hand, and 

 rising with its corresponding leaflet, each closes on its 

 mid-vein ('263), and the pair being folded together, the 

 motion is communicated to the adjacent pairs, as at the 

 left hand in fig. 3, until the whole leaf is folded, when it 

 sinks down on its stalk, as in the right-hand part of the 

 figure. The Venus' Fly-trap (Dioncea) exhibits a very 

 remarkable instance of irritability. If an insect alight 

 on the blade of the leaf, which is thickly fringed with 

 strong bristles, the two sides of the leaf suddenly spring 

 together, the bristles cross and interlock each other, like 

 the teeth of a steel-trap, the fly is imprisoned, and by 

 its struggles to escape it is only bound more closely; nor 

 will the prison open until the fly is dead. The stamens 

 of the Barberry, in the mature state, are so exceedingly 

 irritable, that if yon touch the base of the filament with 

 the point of a pin or penknife, it instantly springs towan 

 the pistil, and discharges its pollen. In this manner 

 the feet of insects contribute to the work of fertilization. 



The motions of the stamens in the Mountain Laurel, and 



some others, are to be ascribed to mechanical means, the 



anthers of the Laurel being confined in their lit > 



ir cells of the corolla by a glutinous substance, which in 



absorbed by the anther as it approaches maturity ; and 



when no longer held, like a strained bow, they restore 



hemselves by an elastic movement, and thus scatter the 



>olleu in the direction of the stigma. The clastic motions 



f certain fruits, as the Balsaniinc and Squirting Cneuni- 



>er, are also imputed to mechanical agency, rather than 



rritability. 



517. SPONTANEOUS MOVEMENTS. A species of Tre- 

 bil (Dcsmodium gyrans) exhibits the most remarkable 

 motions of this kind. Its two small lateral leafl. 

 seen in fig. 1, are in constant motion day and night, ex- 

 libiting constantly a series of violent little jerks, one 

 rising while the other falls; but the large terminal leaf- 

 .et is not affected by these motions, for it only chani: 

 position, like the leaves in most of its tribe, at night, 

 restoring itself in the morning. Cold, and especially the 

 application of cold water, will for a time arrest thcso 

 curious movements, but they are renewed with the return 

 of warmth. Several other plants exhibit similar phe- 

 nomena. 



518. MOVEMENTS OF SPORES. Many of these, espe- 

 cially in the lower orders of Algae, exhibit very remark- 

 able peculiarities of motion. In some instances they 

 swim about in the water, vibrating their cilia with very 

 curious and rapid motions, not unlike those of some of 

 the lower Polypes, until they are ready to germinate, 

 when they fix themselves, and begin to grow. 



519. EFFECT OF POISONS. That plants really pos- 

 sess sensibility analogous to that of animals, is shown by 

 the effect of poisons. Not only will mineral poisons, on 

 being absorbed by the root, produce death by corroding 

 the tissues ; but vegetable poisons will also destroy life, 

 without altering the tissues. Yet there is nothing like 

 the nervous system of animals to be found in the vege- 

 table constitution. The poison must act through this 

 sensibility, which represents or shadows forth the nervous 

 system of animals, and which, like it, is found to bu 

 affected in various lower degrees by stimulants and nar- 

 cotics. 



'When and how doet the Evening Primrose unfold f Clstns Portulacc* 

 Momlng-Olorjr Mlrablllj Goafs-beard. What common names applied 

 What plant* cloje before a torm ? What keep opon ? What plants affixsUx 

 by touch T Describe the pt;ee In Mlmusa. Dsscrlbe the Irritability I 





Vcnna' Fly-trap In tho Barberry. To what may that of the Mountain Lanrcl 

 and tome otlien be referred? Describe spontanoons motion*. Remarkable 

 Instance. Describe. How In the Algm f How do mineral poisons affect pluntf 

 vegetable poison* what does It prove ? 



