Kelley — 2 — Mycotrophy 



to dissolve food materials somewhat as saliva does in animals. It was 

 F. Meyen, in 1838, who came to the modern view that root-hairs 

 serve merely to increase the outer surface area of the root. 



By such studies attention was focused on root-hairs until Botany 

 was firmly moulded to the view that higher plants are nourished by 

 a root-hair mechanism. So positive had Botany become that by 1883, 

 Frank Schwarz (from whom we have quoted much of the pre- 

 ceding paragraph) was able to state without exciting contradiction: 

 "From my researches it may be stated that root-hairs are present on 

 most plants, and when a plant fails to produce root-hairs it may be 

 counted an exception." He listed as exceptions : water and swamp 

 plants, and those the water and salt requirements of which are met in 

 a special way, as in conifers, noduHferous plants and in part by 

 parasites. 



Early Study of Nodules: — Thus it was, not by extended ob- 

 servation or study of plants in nature but by sheer dogmatism that 

 root-hairs came to be regarded as the predominate root structures of 

 higher plants. Hairless roots were considered exceptional, but they 

 were constantly being noted. Malpighi, early microscopist that he 

 was, had described and figured nodules while du Hamel du Monceau 

 in 1758 had stated that such structures were generally found on 

 leguminous plants. Even Meyen, in 1829, who has been accredited 

 with discovery of mycorrhizae, simply described nodules of the 

 alder. Alder nodules were more carefully studied by Woronin in 

 1867 but his inadequate facilities led him to confuse bacterial strands 

 with fungal hyphae. Even to this day there is confused thought 

 about root-nodules for some investigators assert them to be purely 

 bacterial while others consider them fungal. 



Nutrition of Monotropa: — Besides nodulous roots there were 

 obviously other exceptional kinds. The waxy Monotropas that appear 

 in deciduous woods have no apparent root-hairs and were long con- 

 sidered parasites. It was thought that they must be attached to 

 tree roots for they always grew under the trees and in a thick mat of 

 humus and intertangled rootlets, although as early as 1832 Fries 

 had noticed a fungus connected to Monotropa. Several investiga- 

 tors reported on it in that short-lived journal, The Phytologist, and 

 came to the conclusion that, whatever else this plant might be, it was 

 certainly not a parasite. One of the observers, Luxford, in 1844, 



