THE PALMS OF BRITISH IXBIA AND CEYLON. 955 



intercellular spaces or between adjacent cells and derive their 

 food from the living cells by means of hanstoria. The parasite 

 is found in all parts of the leaf, excepting the bundles and 

 bands of sclerenchyma. The reproductive organs arise from the 

 superficial hypha3. The}?- are of two types, sporangia and resting 

 <;onidia. 



The sporangia are formed terminally on the main branches of 

 the mycelium or on short or long stalks borne laterally on these. 

 They vary much in size and shape. On an average they measure 

 oO by 35 ^., extremes 38-70 b}^ 33-42. Poor cultures show even 

 ■smaller ones. The shape is typically pyriform. The narroAv end 

 •of the ripe sporangium is papillate. There are four types of ger- 

 mination, which must be considered as modifications of the one 

 process: (1) The apex of the papilla swells up into a very thin 

 gelatinous vesicle. The protoplasm of the sporangium passes into 

 the vesicle in a uniform granular mass, forms a number of zoospores 

 hj segmentation. The wall of the vesicle ruptures and the ciliated 

 spores escape. (2) Segmentation into zoospores occurs within the 

 sporangium. No vesicle is formed, but the papilla dissolves, or if 

 a vesicle is formed, it ruptures almost immediately. When an 

 •opening is formed, the protoplasm escapes and breaks up at once 

 into free zoospores. Intermediate types between this and the fore- 

 going are met with. (3) The zoospores ripen within the sporangium 

 but, on the opening of the papilla, are not able, from one cause 

 •or another, to escape. They come to rest after a variable period 

 •of movement, round off, become clothed with a wall, begin to ger- 

 minate and pierce the wall of the sporangium. (4) No zoospores 

 are formed. The sporangium germinates by putting out one or 

 several germ-tubes. 



The zoospores measure from 8-10 ^ after they come to rest and 

 assume a spherical shape. Thej^ germinate rapidly by one or some- 

 times two germ-tubes. 



The second mode of reproduction is by resting conidia. These 

 are spherical, thickwalled, and often yellowish when old. They are 

 formed singly at the ends of usually large hj^phse. Intercalar ones 

 are rare. They measure 25-40 /x in diameter, the wall being up 

 to 4 IX thick. The stalk-hypha shows great variety as regards size. 



