THE CONIFERS OF JAPAN. 29 



ahd certainly one of the most ornamental of tlie small Pines ; it 

 may be used as a decorative plant where the larger Pines are 

 unsuitable. 



Before dismissing the Japanese Pines, a circumstance of 

 exceptional interest in connection with two of them should be 

 noticed ; this is Mayr's hypothesis of the existence of natural 

 hybrids between Finns clensiflora and P. Thunhergii. Seminal 

 variations among Conifers are common occurrences, of which 

 many striking instances of known origin are now in cultiva- 

 tion. In the case of the two Pines in question, Mayr detected 

 intermediate forms in which the characteristics of the two 

 species are so intimately blended that they cannot be regarded 

 as seminal variations either of the one or the other. He observed 

 two groups of these supposed hybrids, one approaching nearer 

 the Black Pine (P. Thunhergii) and the other nearer the Eed 

 Pine (P. densiflora) ; he thence infers that one group must have 

 resulted from the opposite cross of the other. When we bear in 

 mind the enormous quantity of pollen produced by a single 

 Pine-tree, which, when shed, is blown by the wind in clouds, 

 sometimes to a great distance, the possibility of the cones of one 

 ■species being fertilised by the pollen of a closely allied species 

 commends itself to us as a very possible natural event. 



To return to our review of the Conifer se of Japan. 



Sciadopitys verticillata, or the Umbrella Pine as it is often 

 called, is one of the most remarkable monotypes in the Order. 

 It has now been in our midst more than thirty years, but there 

 are not yet to be found in this country specimens 30 feet high, 

 or even half 30 feet, or if so they are extremely rare. Com- 

 plaints reach us from all parts that it will not grow, and yet 

 the answer to these complaints is simple enough, and may be 

 thus formulated. Where the Bhododendron thrives the Scia- 

 dopitys will groiu. This means that the soil in which it is 

 planted must be sufficiently retentive to afford a constant supply 

 of moisture to the roots while the tree is growing. Where this 

 supply is intermittent — that is to say, when the Sciadopitys is 

 planted in a soil that is sometimes dry and sometimes wet, 

 according to the changes of weather^ — it will not grow. In the 

 highly saturated atmosphere of Central and Southern Nippon, 

 the Sciadopitys towers to a height of 100 feet. In the moist 

 climate of Cornwall, where the annual rainfall is greater than 



