52 BULLETIN 1380, U. S. DEPARTMENT OF AGRICULTURE 
produced, and so on. This method of reproduction is characteristic 
of the group. Rarely sporangia are borne on short lateral branches. 
The sporangia on germination give out a number of oval or elliptical 
hyaline zoospores. The spores are provided with two motile cilia, 
by means of which the spores are propelled in a drop or film of 
water, as that of a leaf after rain or where covered with dew. After 
a time they come to rest and send out delicate germ tubes which 
penetrate the epidermis either through the stomata or directly 
through the cell walls. 
Another type of sporangium is produced either on the external 
mycelium or internally which does not give rise to motile zoospores 
but germinates in the ordinary way. These spores develop a thick 
wall and are capable of tiding the fungus over periods of dryness. 
These resting spores may be formed in great numbers in the diseased 
tissues of the fruit and are liberated when the tissues decay. 
A third type of spore may be produced by a sexual process 
wherein the male-element antheridium, a globular or oval body, 
fertilizes the oogonium, usually a pear-shaped smooth or rough- 
surfaced hyaline structure, which represents the female element. 
The result of this process is the production of thick-walled smooth 
brown oospores, which germinate under suitable moisture conditions. 
This structure has not been observed for the species. 
When the diseased fruits begin to shrivel, or even before, the 
original cause of the disease is entirely obscured by the rapid attack 
of a number of secondary fungi. Among the first to appear is 
Gloeosporium albo/ubrum. The pink spore jmstules of the fungus 
sometimes appear in great numbers and may be confined to areas of 
the surface not overrun by the Phytophthora. There is some evi- 
dence that Gloeosporium may also cause a disease of the pods. 
Yellowish green pods picked and placed in oil-paper bags for a few 
days would become completely covered with the pink spore masses. 
The fungus appeared to be omnipresent, however. Perfectly green 
and healthy pods when kept for a few days in a closed jar developed 
the spore masses in great numbers. 
The Gloeosporium is rapidly obscured by an excessive develop- 
ment of Diplodia and various molds. 
FLOWER BLIGHT 
The inflorescence of Hevea is frequently attacked by Dothidella 
ulei. All parts of the inflorescence are attacked, causing them to 
shrivel and fall away. Heavy infections were observed in the region 
of Para but none on the upper Amazon. The destruction of the 
flowers naturally a fleets seed production. The seeds are not of 
economic importance, but the significance of the attack has a bearing 
on the maintenance of the fungus in the stand by increasing the 
amount of infectious material. 
In two different cases the floral spikes of Hevea in situations where 
they were crowded against withered or decaying vines were overrun 
and blighted by various species of Aspergillus. (See list, p. 80.) 
This is but a temporary condition and is of no economic importance. 
