904 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



starting well, are checked, the annual increase diminishes, the needles 

 become smaller year by year, and the top dies off. Whole plantations 

 may die off completely, or may recover after a check ; in any case the 

 loss of revenue is considerable. Even where the land is cleared of heather 

 before planting, and where ploughing every few years is resorted to, 

 growth of the Spruce may be unsatisfactory. Good results are obtained 

 when Spruce is planted with Pinus montana as a nurse. The author 

 has endeavoured to find an explanation. After an examination of the 

 possible factors, he fixes on the mycorhiza (fungus roots) of the Pine as 

 the chief agent. On this tree two forms of mycorhiza occur (and are 

 figured) : (a) a racemose form with ectotrophic or external covering of 

 fungus filaments ; (b) a dichotomous form with endotrophic or internal 

 occurrence of the fungus. The Spruce, on the other hand, has only 

 racemose ectotrophic mycorhiza. The author's argument is that just 

 as Clover or other Lcguminosce by means of their root- tubercles (or endo- 

 trophic mycorhiza) provide food materials — chiefly nitrogenous — for cereals 

 and grasses, so the Mountain Pine, with its endotrophic mycorhiza, 

 furnishes nutrient material for the Spruce, which the latter by itself is 

 unable to procure. It is shown that Heather and many other plants of 

 heaths have endotrophic mycorhiza, hence by analogy the Mountain Pine 

 is better fitted for life on the heath than the Spruce. Details are required 

 before the relationship is finally proved. The suggestion that one tree 

 may provide food for the growth of another species is one which has 

 hitherto received little attention, and, if proved, will have an important 

 bearing on forestry. — W. G. S. 



Stachys tuberifera, Notes on the Introduction and Culture 



Of. By E. Brucalassi (Bull. B. Soc. Tosc. Ort. 1, p. 17, Jan. 1904). — A 

 native of China and cultivated for a long time in Japan, where it is 

 known under the name of chono-gi. It was introduced into Europe about 

 1882, and cultivated for the first time in France, thanks to the researches 

 and studies of M. Paillieux. It was introduced into cultivation in 

 Florence for the first time in 1899 at the Eoyal School of Pomology. It 

 belongs to the Labiate, and perennates by means of its white rhizomes, 

 which reach a length of about 5 cm. by 14 mm. in diameter. The 

 constrictions at intervals give the rhizome a screw- or shell-like appear- 

 ance. The square stems are about 40 cm. high ; the stalked leaves are 

 opposite, with crenulate margins, and slightly acuminate. The sessile 

 flowers have a campanulate calyx and purple corolla about 12 mm. 

 long. Fertilisation rarely takes place, and seeds are therefore difficult to 

 obtain. 



It should be planted in a light soil, chiefly for facilitating the digging 

 of it in winter. 



In February the rhizomes are planted at intervals of 30 cm. and at a 

 depth of 5 cm. in furrows 50 cm. apart. When the shoots are 15 cm. 

 high they must be supported and the soil weeded. The tubers are 

 gathered when the aerial shoots are completely withered, i.e. in November 

 or December. The rhizomes can be stored in light, moist sand. 



The plant is quite hardy ; the culture is very easy, inexpensive ; and 

 the production is abundant and remunerative. For eating it is prepared 



