48 DISEASE OF COLOCASIA IN JAMAICA. 
The offsets of diseased tubers, even when very young, contain 
the fungus in their tissues, which are reached by way of the 
tracheids entering from the parent tuber. 
Fig. 2. 
Portion of trarisverse section of head in the early stage of disease; the spota 
correspond to vascular bundles, the hyphæ having discoloured the walls 0 
the tracheids. 
All diseased plants should be burnt, and not buried or used for 
feeding animals, as the resting-spores possess great power of 
vitality, and possibly might resist both latter methods of supposed 
destruction. 
PERONOSPORA TRICHOTOMA, Massee (Plate I. fig. 1); mycelil 
tubi crassi, haustoria vesiculiformia, clavata. Stipites conidifert, 
fasciculati, 2-3-ies trichotomi. Conidia parva, obovoidea, sub- 
globosa, 12x 10 p. Oosporarum episporium fuscum, cristis con- 
nexis subregulariter reticulatum, 35—40 y. 
Conidiophores resembling a delieate white bloom on the sur- 
face or in hollows of the diseased portions of rootstock of 
Colocasia. 
. HETEROSPORIUM ÜoLocasız, Massee (Plate I. fig. 2); hyphis 
fasciculatis, hic inde furcatis, olivaceis; conidiis oblongis, uni- 
septatis, constrictis, granulatis, pallide olivaceis, 25-30 x 10-12 p. 
Forming olive-green patches on the diseased parts of Colocasia. 
CEPHALOSPORIUM ACREMONIUM, Corda, Ic. Fung. iii. p. 29. 
Var. with uniseptate conidia. (Plate I. fig. 3.) 
Parasitic on the hyphe of Heterosporium Colocasia. 
n 
d ccc 
