Lecture II — 33 — Occurrence of Mycorrhizae 



rhizae while smaller families are entirely ignored. Thus, one dozen 

 genera of Ranuncnlaceae are reported mycorrhizal and twelve of 

 Cruciferae; twenty-six genera of Papilionaceae are reported which 

 is the record for the Dicotyls ; but as many or perhaps most of 

 these cases are bacterial they are dubiously considered as mycorrhi- 

 zal. The next largest record is of the Compositae with 25 genera 

 reported. 



There are conflicting reports : Thus, Podophyllum is termed 

 mycorrhizal by Lohman and non-mycorrhizal by MacDougal; 

 Benzoin is mycorrhizal according to Henry but non-mycorrhizal ac- 

 cording to MacDougal; Ailanthus is non-mycorrhizal according 

 to Stahl and to Duthie but endotrophic according to KleCka and 



VUKOLOV. 



Then there are families that are listed on the basis of single 

 reports, as the Calycanthaceae (Asai), Menispermaceae (McDougall 

 & Liebtag), Sarraceniaceae (MacDougal), Pittosporaceae 

 (Asai), Sterculiaceae (Asai), Tamaricaceae (Stahl), Cistaceae 

 {Vtrotta) , Nyssaceae (Henry), Diapensiaceae (Asai), Myrsinaceae 

 (Asai), Phmibaginaceae (no mycorrhizae according to Costantin) ; 

 and these reports are not confirmed nor amplified. 



In a number of families there is an amazingly large number of 

 genera yet to be examined : Thus, in the Borraginaceae with 85 

 genera and 1500 species but 4 genera and 6 species have been stud- 

 ied for mycorrhizae; in the Labiatae but 10 genera and 14 species 

 have been studied amongst the total of 160 genera and 3000 species ; 

 in the Scrophiilariaceae but 6 genera and 18 species have been 

 studied amongst 180 genera and 3000 species; while the Bignonaceae 

 with 100 genera and 600 species is entirely untouched. In the 

 great family of Compositae with its thousands of species there are 

 but 54 studied for mycorrhizae. 



In many of the Dicotyls we would expect to find phycomycete 

 mycorrhizae as in the Violaceae of which 12 species are termed 

 mycorrhizal but we have no detailed studies upon them. Two species 

 of Liniim, 3 of Oxalis, 3 of Hypericum, 7 of Epilohium, five of 

 Primula, six of Campanula are listed as mycorrhizal ; and we await 

 further information as to whether the concomitant fungi are phyco- 

 or basidiomycetes. 



Several special cases may be noted : Thus the insectivorous 

 plants have received some attention, the Droseras at the hands 

 of Frank, Hoeveler, Schlicht, and Peyronel; Sarracenia, of 

 MacDougal. Stahl was interested in the Polygalas, terming them 



