42 JOURNAL Of THE ROYAL HORTICULTURAL SOCIETY. 



food, viz. Bartsia aljnna and Lathrcea sqitamaria, both belonging to the 

 tribe Euphrasiece, mentioned above. 



This species of Bartsia produces little buds underground, the leaf 

 scales of which contain glands on their inner surface capable of 

 absorbing animal matter, while the numerous fleshy scales which cover 

 the rhizomes of the toothwort {Lathrcea) are provided with chambers, 

 into which minute creatures crawl and are thus digested ; certain glands 

 putting out protoplasmic hairs to catch the prey, while other glands appear 

 to absorb the nourishment.* 



Sa2:)rophytes. — With regard to the origin of saprophytes, it has been 

 suggested from their abundance in tropical forests — the whole number of 

 species known being 160, 122 of which are tropical — that they arose in 

 the deeper and darker parts of the forest, where assimilation by sunlight 

 was greatly impeded, in a soil rich in nutritious matters resulting from 

 the perpetual decay of vegetation. Another possible origin of many 

 greenless saprophytes may be that they were formerly parasites which 

 have changed their habit of life in now living solely on decomposing 

 organic matter. Greenless saprophytes, therefore, if they were presumably 

 at first parasites, lost their parasitic habit, and became changed to sapro- 

 phytes where light was feeble. 



Although this would seem probably to have been sometimes the case, 

 it does not preclude the possibility of an ordinary green plant becoming 

 saprophytic. As a case in point, a species of Fern (Gramatophylhim) 

 has been known to produce its aerial roots among decayed vegetable 

 matter. In this case on a careful examination I found that the surface 

 of the roots in contact with it had developed quantities of " absorbent 

 hairs." These were doubtless induced to be formed by the presence of 

 nutritive matter.t 



In another case I found that the rhizomes of a musk plant happened 

 to have penetrated a rotten log, running parallel with the grain. They 

 were quite white. Each branch terminated with a bud composed of very 

 arrested scales. The outermost tip protecting the apex was hardened and 

 brown (physiologically acting as a root- cap). The epidermis was without 

 any stomata, delicate and "epithelioid" in character. It had a thick 

 cortex of thin-walled cells apparently full of water. There was a very 

 small central cylinder. Fine thread-like roots were sparingly given off. 

 These were covered with extremely delicate unseptate hairs penetrating 

 the wood in all directions. So far they would seem only to have absorbed 

 water, but on testing the starch, which was sparingly scattered through 

 the cortex, I found that it assumed a bright red colour with tincture of 

 iodine, and not the usual violet tint. Now, this red colour is characteristic 

 of saprophytes. 



Special Peculiarities of Saprophytes. — It has been already suggested 

 that greenless saprophytes are a secondary result of parasitism. Some, 

 such as the green-leaved Melampyrwn, can derive nourishment from dead 

 wood much in the same way as it does from a living root ; but the forma- 

 tion of specially absorbing organs like those of parasites is not known, 



* They will be found both described and figured in Oliver and Kerner's Natural 

 History of Plants, i. p. 137, tig. 25. 



t Journal B.H.S. vol. xvi. p. xxiii, 1893. 



