SECTIONAL TRANSACTIONS.—K. 357 
Cryptomyces maximus, Rehm. This fungus disease is characterised by long raised 
blister-like patches, black with lobed edges, and the lesions form a means of entry for 
the semi-parasite. 
Scleroderris fuliginosa, Karst., which appears frequently round the edge of the 
scars formed by the Cryptomyces, forming an aggregate of fructifications in size, 
colour, and shape not unlike rape seed. Apparently this is not a primary parasite, 
but let in by other fungi, does harm. : 
Myzxosporium scutellatum (Otth) Petrak., on willow twigs killed or injured by any 
of the above, or other fungi, forms numerous minute greyish fructifications, saucer- 
shaped. This appears to be practically a saprophyte. 
6. Miss M. J. F. Witson.—Rhabdocline Pseudotsuge Syd., a hitherto 
unrecorded Disease of Douglas Fir in Britain. 
This disease first occurred in the south of Scotland about 1920, and appears to have 
been introduced from N.W. America, where it has been causing defoliation of the 
Douglas fir since 1911. Up to the present time only the blue Douglas has been attacked 
in this country, but infection experiments are being conducted in order to ascertain 
whether the green Douglas isimmune. The parasite is Rhabdocline Pseudotsuge, Syd., 
a new genus and species of the Phacidiacez, named and described by Sydow in 1922. 
Asci are produced in May, the ascospores being at first unicellular, later bicellular, 
some even dividing to three or four cells. Finally one cell becomes dark coloured 
and produces a germ tube, the others remain hyaline and do not germinate. 
7. Mr. J. 8. L. Warvie.—Rhizosphera Sp. causing Leaf Fall among 
Conifers. 
Rhizosphera Kalkhoffiti, Bubak, has been found frequently on the glaucous varieties 
of Picea pungens, which are often grown in this country as ornamental trees. Large 
numbers are imported from the Continent, and since the fungus is known to be wide- 
spread in Central Europe, it is probable that the disease has been imported on 
_ P. pungens. 
; The disease causes the needles to become pale in colour and take on a purplish- 
brown tint, followed by defoliation. The small black fructifications are developed 
: on the surface of the needle, immediately above the stomata, completely blocking 
the latter. Numerous minute spores are formed in the fructifications and these 
: spread the disease. 
: Rhizosphera sp. has also been found on other species of the spruce, including 
_ P. Sitchensis and P. excelsa, as well as on Abies pectinata and Pseudotsuge Douglasii. 
The fungus has been found on trees up to fifteen years old, and there is a danger that 
_ it may cause defoliation on these important forest trees. 
| 8. Dr. J. W. Munro.—Recent Work on the Cockchafer. 
9. Mr. W. E. Hitey.—Respective Advantages and Disadvantages of Long 
and Short Rotations. 
Detailed calculations have been made for European larch to show how much loss 
is likely to be incurred by prolonging rotations beyond the financial optimum in order 
that the costs of the silviculturists’ demands may be assessed. The following results 
_have been given by calculations from a yield table constructed to represent average 
conditions of growth and market for second quality larch. 
(1) Plantations may yield 6 per cent. compound interest on a 35-year rotation 
; and 5 per cent. on a 70-year rotation, notwithstanding the fact that the sale value of 
an final crop at 35 years is estimated at £88, and at 70 years £220 per acre. If £30 
less than the amount stated were obtained at the thirty-fifth year, the financial yield 
_ would still be 5 per cent. on the shorter rotation. These rates of interest are very 
nearly free of income tax. 
(2) The mean gross income is about £3 13s. per acre per annum on the 30-year 
rotation and £4 12s. on the 70-year rotation. 
1 (3) The mean annual expenditure (exclusive of felling), nearly all of which repre- 
ora wages, is about 17s, 9d, per acre for a 30-year rotation and 15s. for a 70-year 
- rotation. 
