POI 



[ 729 ] 



POL 



ylandulosa, the Manchineel, the Tanyhin, \ 

 Sapium laurocerasus, and Camodadia \ 

 dentata, are equally deleterious to man. 

 Gardeners who have merely rubbed the i 

 leaves of the latter between their ' 

 lingers, have had swollen bodies and 

 temporary blindness. Wounds from 

 pruning knives smeared with the juices ' 

 of such plants are like those from | 

 poisoned arrows. 



POISONS. Soils containing obnoxious ; 

 ingredients are certain introducers of ' 

 disease and premature death. An \ 

 excess of oxide of iron, as when the | 

 roots of the apple and pear get into an j 

 irony-red gravelly subsoil, always causes i 

 canker. In the neighbourhood of cop- 

 per-smelting furnaces, not only are j 

 cattle subjected to swollen joints and ; 

 other unusual diseases, causing decre- \ 

 pitude and death, but the plants also i 

 around are subject to sudden visitations, 

 to irregular growths, and to unwarned 

 destruction ; and a crop once vigorous 

 Avill suddenly wither as if swept over 

 by a blast. There is no doubt of this 

 arising from the salts of copper, which 

 impregnate the soil irregularly, as the 

 winds may have borne them sublimed 

 from the furnaces, and the experiments 

 of Sennebier have shown that of all 

 salts those of copper are the most fatal 

 to plants. That they can be poisoned, 

 and by many of those substances, nar- 

 cotic as well as corrosive, which are 

 fatal to animals, has been shown by 

 the experiments of M. F. Marcet and 

 others. 



The metallic poisons being absorbed, 

 are conveyed to the different parts of 

 the plant, and alter or destroy its tissue. 

 The vegetable poisons, such as opium, 

 strychnia, prussic acid, belladonna, 

 alcohol, and oxalic acid, which act 

 fatally upon the nervous system of 

 animals, also cause the death of plants. 



The poisonous substance is absorbed 

 into the plant's system, and proves 

 injurious when merely applied to its 

 branches or stem, almost as much as 

 if placed in contact with the roots. 

 Ulcerations and canker are exasperated 

 if limo be put upon the wounds, and 

 \vheii Dr. Hales niudo a Golden Jlennet 

 Apple absorb a quart of camphorated 

 spirits ol' \vinc through one of its 



branches, one-half of the tree was 

 destroyed. 



POI'VKEA. (Named after N. Poivre, 

 a Frenchman. Nat. ord., Myroboldns 

 [Combretacese]. Linn., 10-Decandria 

 i-Monogynia. Allied to Combretum.) 



Stove evergreen climbers. Cuttings of short 

 stubby side-shoots, as fresh growth commences, 

 in spring, in sand, under a bell-glass, and with 

 a little bottom-heat ; sandy loam andfibry peat, 

 with pieces of charcoal. Winter temp., 55 to 

 60 ; summer, 60 to 85. 

 P. Afxe'lii (Afzelius's). 10. Scarlet. April. 

 Sierra Leone. 1826. 



barba'ta (bearded-petated) . 10. White. 



Maranha. 1820. 



cocci'nea (scarlet). 20. Scarlet. September, 



Madagascar. 1818. 



como'sa (tufted). 20. Purple. Sierra Leone, 



1822. 



deca'ndra (ten-stamened). 20. White. April. 



East Indies. 1826. 



interme'dia (intermediate). 15. Scarlet. 



April. Sierra Leone. 1823. 



macrophy'lla (large-leaved). Scarlet. April. 



Isle of Bourbon. 1838. 



POLANI'SIA. (From polys, many, and 

 anisos, unequal ; many stamens of un- 

 equal lengths. Nat. ord., Capparids 

 [Capparidaceas], Linn., ll-Dodecandria 

 1-Monogynia. Allied to Cleome.) 



Hardy annuals, flowering in June. Seeds, in 

 | a slight hotbed, under a glass frame, in March 

 | and April, and pricked out and finally placed 

 j in the open ground in the beginning of June. 

 P. Chelado'nii (Chelandon's). l. Hose. East 

 Indies. 1792. 



dodtca'ndra (twelve-anthered). 1$. White. 



East Indies. 1795. 

 I grave'olens (strong-smelling). l. Pinkish. 



Canada. 

 j uniglandulo'sa (single-glanded). 1. White, 



red. Mexico. 1823. 

 1 visco'sa (clammy). 2. Yellow. East Indies. 



1730. 

 -- icosa'ndra (twenty - anthered). l. 



Yellow. Ceylon. 1730. 



POLEMO'NIUM. Greek Valerian. (From 



I polemos, war ; according to Pliny, a 



dispute about its discovery led to war- 



fare. Nat. ord., Phloxworts [Polemo- 



niaceae]. Linn., 5-Pentandria l-Mono- 



I 



Hardy herbaceous perennials. Seeds; but 

 generally division of the plant ; common garden 

 soil. 



P. casru'lcum (blue). 2. Blue. June. Britain. 

 --- a'lbum (white). 2. White. June. 



Britain. 

 --- grandiflo'rum (large - flowered;. 



Brown. June. India. Biennial. 

 --- macula' turn (spotted). 2. Striped. 



June. Britain. 

 --- pili'ferum (hairy). Blue. June. 



North America, 



