406 



KNOWLEDGE. 



OcTOBru. 1911. 



almost iici;lii,'ible. 

 in Sciitland. N." 



The weather of the week ended September 9th was \er\- 

 fine and dry tfeneralK-, bnt with thnnderstorms on the 4th 

 and Sth. Temperature was again above the average, the 

 excess in most parts of England being large, as much as 7^' 8 

 in England, S.W., and 9°-3 in the English Channel. The 

 highest readings were again \er\- high. o\er 90 in man\' 

 cases, and reaching 93" at Bath and Cambridge and 94° at 

 Greenwich and Kannds. In the extreme North, however, the 

 temperature was low ; at Lerwick the maximum was onl\- 59". 

 The lowest readings were 31° at West Linton, .ind M" at 

 Balmoral. ( )u the grass the temperature was \er\ low for 

 the time of ye.ir, falling to 26° at Llanganmiareh. 27° at 

 Crathes. and 30' at Balmoral and Colmoni'll. 



Rainfall was again greatly deficient in all district: 

 except in Scotland, N,, the total fall was 

 At many stations the week was rainless. 



Bright sunshine was in excess except 

 where it was just below the normal. The district means 

 varied from 25 hours (26%) in Scotland. \'.. to 68 hours 173%) 

 in Ireland. S. The sunniest stations werre X'alencia 78-1 

 hours I84",>), Jersev 77 -J hours (84%) and Terdn- 74-9 hours 

 (81%). 



The mean temperature of the sea water varied from 54° '0 

 at Lerwick to 68° -0 at Eastbourne, 



The \\ eek ended September 16th. was cooler and less settled 

 than tlinsc inunediately preceding it. with thunderstorms on 

 tile 1 Uli and 12th. Temperature in many parts differed but 

 little from the average, but in the Southern districts it was 

 still above the normal. The highest readings were 88° at 

 Greenwich. 87° at Margate and Tunbridge Wells, and 86° at 

 Westminster. Cambridge and Geldeston. The minima fell 

 below the freezing point on the 16th. to 31° at Colmonell. and 

 to 28° at Llangammarch Wells. On the same day ii° was 

 recorded at Hereford, while on the 13th the minimum at 

 Balmoral was i2°. On the grass, temperature fell very low . to 

 14 .it Llangammarch, 22° .it Hereford and 27 at Colmonell. 



Rainfall was considerably in excess in England, X.W., where 

 it was more than double the average. In Scotland. N., it was 

 drv. and only one-third of the usual amount was collected. 



Bright sunshine exceeded the average, except in Scotland \i. 

 and in Ireland, the excess in England S.E. exceeding two 

 hours per day. The sunniest stations were Eastbourne 

 59-5 hours (67%), Hastings 58-8 hours, (66%), and Guernsey 

 58-9 hours (66%). At Westminster the total duration was 

 48-3 hours (54%). 



The temperature of the sea water was as low ;is 49 at 

 Scarborough, and rose to 68" at Margate and at the Shi])- 

 wash Lightship. 



MICROSCOPY. 



By A. W. Sheppard, F.R.M.S., 

 iii'itli tlic iissistiiiicc of the foUoti'ing iiiicroscopists : — 



,\r1HUR C. BaN'FIELO. .\RTHUR I'^ARLAND, F.R.M.S. 



The Rev. E. W. Bowei.i., M.A. Richard T. Lewis. F.R.M.S. 



James Burton. Chas F. Roussei.et. F.R.M.S 



Charles H. Caffvn. D. J. Scourkieli>, F.Z.S., F.R.M.S. 



C. D. Soar, F.I..S.. F.R.M.S. 



MACROSl'OI'UL'M (FRIES).— The large compound spores 

 of this fungus form handsome micro-objects, even for low 

 powers, and are by no means difficult to obtain, especially in 

 the autumn. The genus contains both saprophytic and 

 parasitic species, though there is much doubt as to their 

 exact limitations, .Some are found growing on decaying 

 cabbage leaves, bean pods and other vegetable refuse ; a fine 

 species M. sarciniila (Figure 1) is not at all uncommon on 

 over-ripe melons, where it appears as black velvety patches, 

 sometimes of considerable extent. It would be difficult, 

 perhaps, to decide in many cases whether the fungus is a 

 saprophyte or a true parasite. Another example, more 

 fre<)uent than welcome, is well-known to growers of tomatoes. 

 It occurs both on the plant and on the fruit, but chiefly on 



the latter, and anyone wishing to obtain specimens for 

 examination should look over some poor samples, when 

 the parasite — as it almost certainly is in this case — will 

 be found as black or olive-green patches of various sizes, 

 usually sunk a little below the general surface. On cutting a 

 thin slice from the region, it will be discovered that the 

 underlying tissue is permeated by the somewhat coarse thread- 

 like mycelium of the fungus, and occasionally the spores are 

 developed in this situation. One species, named M. solnni. 

 attacks potatoes and may do much damage, particularly to 

 the foliage and stems, though it also attacks the tubers, and 

 may be transmitted, by means of the "seed" (dormant budsl 

 used for planting, to a subsequent crop. This is now believed 

 bv competent authorities to be the same species as that found 

 on tomatoes, M. tomato (Cooke), which appears likely, as the 

 hosts are so closely related. There is a great similarity 

 between all the species of the genus ; the vegetative body 

 consists of a web of mycelium ramifying in the substratum, 

 but usually not very large in amount ; this approaches 

 the smface and there throws up short, jointed, mostly simple 

 stems, which bear the large many septate spores. These vary 

 a good deal in shape and size within the same species, and 



I'IGIIRK 1. 



FiGliRK 2. 



each division — which is in effect a distinct spore — ina\- under 

 favourable circumstances put out a tube (hypha) which gives 

 rise to a new fungus plant. An interesting experiment may 

 easily be made with the tomato species. If some of the spores 

 are placed on a fruit with uninjured cuticle, it will be found 

 they are unable to penetrate it ; but if a wound is made or 

 they are placed on a cut surface, they quickly germinate and 

 in a short time a fresh crop of the fungus and a plentiful 

 supply of spores is obtained. It is necessary to keep the host 

 in a suitable condition of warmth and moisture, which may be 

 achieved by placing it in a saucer with a little water, covered 

 by a tumbler, in a warm situation. The experiment illustrates 

 the danger of infection through abrasions of the resisting 

 outer surface, by what are known as " wound-parasites." 

 Some of the species are known to be the conidia- 

 bearing stage of an ascomycetous fungus. Dr. Cooke says that 

 such is the case with M. sarcinula, and that it is a condition 

 of the common little fungus Sphitcria licrbaniiii. which is 

 plentiful on various herbaceous plants, and looks — under 

 moderate magnification — like little black wine flagons. 

 Figure 1 is a representation of M. sarciiiitht. In Figure 2a 

 .are seen the spores of a species which was found growing 

 inside a Tangerine orange. The hyphae appeared to be unable 

 to emerge through the thick peel, but when a part of this 

 was removed, the spores were produced in great quantity. .A.t 

 b is figured an example of M. toiiiato. on the right hand are 

 shown some spores commencing to germinate. .At c part of a 

 spore is represented emitting a mycelium tube from nearly 

 every division and is taken from Professor Massee's " Text 

 Book of Plant Diseases." The species is M. iinhilc. which 

 occurs on carnations. , „ 



NOTE.— The figure of .-Xnabaena — " Knowledge," Sep- 

 tember, page 354 — was unfortunately wrongly placed. To agree 

 with the text it shovild be turned till the part towards the North 

 is at the South-east. J. B. 



