150 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



"Floral Structures/' in which he deals with nutrition, temperature, and 

 soil as affecting the two essential elements. 



Among fruits these causes all operate to some extent, though not 

 equally, on the same plants. Perhaps the most remarkable is the 

 behaviour of Strawberries under different climatic conditions, as shown by 

 the European varieties introduced into North America, and even by the 

 varieties raised in the United States and grown in widely separated 

 districts. Some of these have become staminate only and others pistillate 

 only ; yet in Great Britain we seldom have any prolonged serious trouble 

 in this respect, except with those of the 1 Hautbois ' type. In all the 

 American lists it is usual to state, in the description, which Strawberries 

 are staminate and which pistillate, and when the latter are planted in 

 beds a line of a variety which produces pollen freely is planted with the 

 others to ensure fertilisation, about one line to ten being found sufficient 

 for the purpose. A typical American variety which will illustrate this 

 is 1 Crescent Seedling.' It is distinctly pistillate in the United States, 

 whereas in this country it produces perfect flowers and sets its fruit most 

 readily, cropping heavily in favourable seasons. 



A well-known British variety, ' Stirling Castle,' which is also pistillate 

 in America and does not set its fruit without the aid of pollen from 

 another variety, is here quite self -fertile and bears constant crops, being- 

 one of the varieties especially favoured by some large fruit preservers for 

 jam making. Whether it is the greater heat of summer or the colder 

 winters of North America which produce this floral unisexuality it is 

 difficult to determine, but in England I have grown the ' Koyal Hautbois ' 

 in warm soils in Surrey and Kent that has proved quite fertile, while the 

 same variety on cold soils in Bedfordshire and elsewhere has proved con- 

 tinually unfertile owing to the suppression of stamens and pollen. 



The evidence varies greatly, and perhaps that recorded is not always 

 strictly reliable, owing to some circumstances being omitted ; but it 

 appears generally that the staminate portion of the flower is more readily 

 affected by changes of temperature than the pistil ; but this is not the 

 case when the temperature falls below freezing point, as then according 

 to my observations, which have extended to several thousands of flowers of 

 our principal fruit trees, the pistil and stigma are the more quickly injured, 

 though something depends upon the stage the flower has reached. But 

 even in small unopened buds of Apples, Pears, Peaches, Apricots, Plums, 

 Cherries, Gooseberries, Currants, and Strawberries, I have repeatedly found 

 the pistil destroyed, or so injured as to be useless, when the stamen showed 

 no damage and subsequently produced pollen. The greatest damage to 

 the stamens appears to result from low temperatures, with sudden varia- 

 tions and abundant moisture, and this is in accord with the observations of 

 Mr. Meehan and others to the effect that the staminate element is more 

 readily affected by a rise in temperature than the pistillate part, and it is 

 thus rendered liable to injury or check by sudden alterations of tempera- 

 ture. It was noted by that observer that in some years with warm days 

 early in spring the catkins of the Hazel would become fully developed 

 " some weeks before the pistillate flowers," with the result that the latter 

 were then usually unfertilised. In a collection of many varieties of nuts 

 there is some natural difference in the time of flowering, and the evil 



