15- Note on a M 



(Ananas sativus, Schult.) 



By P. F. Fyson. 

 [With Plate IX.] 



The Pine-apple as is well known consists of an aggrega^ 

 of numerous spirally placed flowers, the perianths of which are 

 contiguous and form the edible part of the fruit. 



In the specimen shown on the screen it will be seen that 

 the whole inflorescence is broadened out considerably and has 

 assumed an appearance which recalls on a gigantic scale a 

 variety of the Celosia cristata L. of horticulture. There is also 

 a general phyllody of the floral parts, so that while in places the 

 separate flowers can be distinguished, along the central ridge 

 this is not possible. 



This monstrosity was brought to me by Mr. LI. Jones of 

 Madras, who has for many years grown choice varieties of the 

 fruit in his garden. He had, he told me, several plants spoilt in 

 this way, this year, but had destroyed the others. The specimen 

 had been cut off above the leaves, so that there was no chance 

 of keeping it alive, and with the idea of following the develop- 

 ment of any possible parasitic organism, it was allowed to dry, 

 and not preserved in fluid. 



Sections were made from the axis of the inflorescence, and 

 examined for fungi, but no hyphae were found. In certain 

 parts, however, the tissue was seen to contain bodies which 

 appeared to be of a plasmodial nature. They possess no cell 

 wall, and as will be seen from micro -photograph shown on the 

 screen, vary considerably in shape and size. Some are confined 

 to one cell "only, and have one nucleus, others spread through 

 two or even more cells, and have several nuclei. The tissue 

 so attacked is the general ground parenchyma, a few cell-layers 

 below the epidermis ; and as the plant dried and the tissues 

 shrank the parts most affected, and especially the phyllodineous 

 1 oral i >arts , became black. No spores or resting cells were seen. 

 The cause of the malformation appears therefore to have 

 been an intracellular plasmodium, which had entered the plant 



probably through the roots. 



• Malformations of different kinds have long been studied 

 and a considerable literature has grown up about them. .But 

 the earlier study was directed mainly to the evidences afforded 

 by them of the morphological identity of different organs of 

 toe plant. Several have in recent years been shown to be due 

 to parasitic fungi, and a somewhat similar phyllody oi gram- 

 Plants is known to be due to various species of Sclerospora 

 °ne of the Oomvcetes. I have not been able to find any record 

 oi phyllody being traced to a plasmodium, as appears to have 

 been the case here. 



