140 



correspondents scattered throughout the United Kingdom. The 

 preparation of these reports involved a considerable amount of 

 laboratory work, as in the case of unusual or little known diseases 

 the presence of one or more fungi on ihe diseased portion did not 

 necessarily prove them to be individually or collectively the cause 

 of the mischief. Under the circumstances each fungus present had 

 to be obtained as a pure growth, and afterwards each one tested 

 separately as to its power of primarily reproducing the disease on 

 a healthy plant of the same kind as the diseased one from which 

 the infecting material was obtained. Bearing on this question, it 

 may be stated that extended observations strongly suggest, and in 

 many instances prove, that, apart from the " rusts " {Uredineae), 

 " smuts" (Ustilagineae), and certain other truly parasitic forms, 

 fungi are not so frequently the primary cause of disease as they 

 are generally supposed to be. For example, the minute fungus 

 called Pythuim deoaryanum, Hesse, is considered the primary 

 cause of the « damping off " of seedlings. In reality this fungus 

 can only grow in a very damp situation, and consequently only 

 destroys seedlings that are growing in damp, badly ventilated and 

 badly lighted places. When seedlings are growing in open ground 

 exposed to light and air, they resist infection by the fungus. 

 Hence « damping off " is primarily due to bad cultivation. The 

 nost of fungi known as wound-parasites are all secondary agents in 

 promoting disease, the primary cause being the agent causing 

 injury to the tissues, and thus enabling the fungus to enter. The 

 punctures made by mites, " green fly," " scale insects," &c, serve 

 as starting points through which fungi gain an entrance to the 

 living tissues. 



The exceptional weather of last season was the cause of some 

 unusual forms of injury to plants. The somewhat severe late 

 rrosts suddenly following a period favourable to rapid growth, 

 resulted in i.he collapse and death of the young foliage of many 

 icmas ot plants. Cabbages suffered severely. The sudden thaw- 

 ing or tne frozen leaves caused the epidermis of the under surface 

 ot the leaf to separate from the adjoining tissue. A few days 

 later, when the comparatively uninjured upper surface of the leaf 

 again commenced to srrow.it assnmArl a ™,.wi «,«„«i,„«^ „™*ov. 



ance, due to the unyielding dead epidermis. Eventually leaves 

 thus injured shrivelled and died. The leaves of various ever- 



greens, Aucuba, &c, were also injured in a similar way. 



rtJ 1 ^ 01 !?^ 1 ?' a ? ong other sub J e cts, were also investigated in 

 K dre " ^oratory :-A disease attacking apples from Cape 

 Oolonj ; the transmission of disease in potatoes from one genera- 



nTJnr 11 T b ? ? eanS of bybernating mycelium in the tubers ; 

 £?»£♦? ra P ld deca y <> f ripe fruit; the cause of "winter- 

 rot in potatoes ; « heart-rot" of swedes and mangolds, &c. 



tJ ™n£. Ur8erieB ^ J? 1 * farm8 > 8ituated in different parts of 

 on dSes PUrp ° Be ° f 8tud y in S and reporting 



vamd^, ?C Z1De tf S March --The plants figured are : Aloe 

 deowmYrtt B ^\Bl^harocaly X spiraeoides, Stapf, Primula 

 vedlum J?!', Ca ™£ ora coronate, Hook. & Arm, and Paphio- 

 pedilum villosum, Pfitzer, var. anwmense, Rolfe. The Aloe is 



