PLANTS IXSECTICIDAL PROPERTIES. 47 
Polygonum pennsylvanicum L. Smartweed. United States. 
Washburn (93, p. 35) determined that a decoction had no effect on 
the horn fly. 
Pongam pinnata (L.) W. F. Wight. Fabaceae. A tree found in India, Ma- 
layan Islands, and northern Australia, cultivated in Florida. 
The writers' results are given on page 23. 
Primus spinosa L. Rosaceae. Blackthorn. Sloe. Europe. 
Von Mueller (91, p. 430) reports that it is hardly at all liable to 
attack by insects. 
Pteridium aquilinum (L.) Kuhn. Polypodiaceae. Bracken. 
In Austria the leaves are placed in the bed as a protection against 
vermin (6). 
Pulicaria dysenterica (L.) Gaertn. Asteraceae. Synonym: Inula dy sent erica 
L. Fleawort. Southern Europe. 
Lyons (53. p. 384) calls it an herb insecticide. 
Passerini (66) found the action of the flower heads uncertain 
against flies, fleas, and ants. 
Pulicaria vulgaris Gaertn. Synonym : Inula pulicaria L. Europe. 
Kalbruner (47) reports that the flowers were entirely inactive 
against flies. 
Quillaja saponaria Molina. Rosaceae. Soapbark. South America. 
Parker (65, p. 7) used soapbark as a spreader and found that it 
never killed more than 21 per cent of the prune aphids sprayed. 
Rhinanthus crista-galli L. Scrophulaeiaceae. Rattlebox. Northern Eu- 
rope, Asia, and North America. 
Lyons (53, p. 395) lists it as a plant insecticide. 
Rhus coriaria L. Anacabdiaceae. Sumac. Europe. 
Von Mueller (91, p. 461), quoting Sorauer. says: " Carves records 
that this plant, when in proximity of vines infested by Phylloxera 
vastatrix, destroys this insect." 
Reymond (70) buried a bag of sumac (Rhus sp.) leaves around 
the base of each apple tree infested with the woolly aphis (Aphis 
Janigera). He noticed no effect the first year, but the second year 
the experiment was very successful. He thought that the tannin in 
the ripe sumac leaves either killed or repelled the aphids. 
Ricinus communis L. Euphorbiaceae. Synonyms: R. vulgaris 1 Mill., R. rnedi- 
cus Forsk. Common castor-bean. Southern Asia. 
It is reported (5) that in 1886 this plant was found efficacious in 
freeing rooms of insect life, the leaves containing a substance which 
is fatal to flies and other insects. 
Riley and Howard (74. p. 359) quote a medical journal to the ef- 
fect that in Egypt castor-bean plants, when grown about houses or 
when the leaves are placed in rooms where mosquitoes are present. 
are effective repellents, but Howard (44, V- &$) denies that these 
plants when grown about houses act as; mosquito repellents, 
