n6 



The Scottish Naturalist. 



proportion. Proliferous flowers were observed on Brassica nigra 

 and Biscutella auriculata ; petalody of individual stamens in one 

 or more flowers on one example of Cochlearia officinalis, on three 

 of Eruca saliva, on one of Lepidium sativum, and on one of 

 Biscutella. In some flowers of Biscutella, the calyx was made up 

 of four whorls, each of two sepals. The appearances in the species 

 of Malcolmia were less striking. 



From these experiments the conclusion is permitted that the 

 greater number of the Valerianacece and of the Cruciferw must 

 behave in the same manner. As against the positive results, which 

 followed with the certainty of a physical or chemical experiment, 

 certain observations in which the expected result did not follow 

 are of no weight. I do not doubt in the least that by a suitable 

 procedure double flowers could be produced, e.g. in Valeriana 

 alliarioefolia, or in Valerianella carinata, and Szovitsiana, if the 

 moment for setting the experiment in action were rightly chosen. 



In Linaria Cymbal aria I obtained metaschematic flowers with 

 several spurs and free petals. The results were less noteworthy 

 in Tinnantia fugax, Bellis perennis, and Primula acaulis. 



All the anomalies above-mentioned are the results of infection, 

 produced by a parasite as their cause. I gave rise to them by 

 laying upon the buds of the plants in question degenerated buds 

 of Valeriana tripteris, which I found in the wild state in the 

 vicinity of Innspruck, and which, as direct observation proved, 

 harboured Phytoptus. The results differed according as the plants 

 experimented upon afforded proper nourishment to the Phytoptus 

 or the reverse. In the former case the Phytoptus established itself 

 upon the food-plants, and multiplied; in the latter case its stay 

 was of short duration, as I have approximately proved by time- 

 consuming observations in a number of species. But the specific 

 nature of the plant must also be taken into account. Thus in one 

 both the organs of vegetation and those of reproduction may be 

 affected, in another only the true leaves or the flowers, while the 

 flowers or the true leaves respectively remain intact. 



If now the food-plant is a good host for the parasite, and is 

 much infested by it, the plant assumes an appearance, even from 

 a distance, almost as if it were tenanted by plantlice (Aphides or 

 greenfly) ; it is starved and crippled, and does not flower. One 

 could observe the Phytoptus in numbers, especially if the plants 



