LACK OF SPREAD OF ENDOMYCORRHIZAS OF CENTAURIUM (GENTIANACEAE).

Seedlings of Centaurium died in the absence of inoculum of vesicular-arbuscular (VA) mycorrhizal fungi in a soil low in nutrients. The morphology of endomycorhizas of Centaurium and Eustoma grandiflora (Raf.) Shim, differed from that of commonly studied VA mycorrhizal hosts in that coils, arbuscules and vesicles were formed but rapidly collapsed. Endomycorrhizal infection spread down the roots of Centaurium erythraeq Rafn. when it was grown with a companion plant, Trifolium dubium Sibth. but when grown alone infection was restricted to the vicinity of the inoculum. Several different VA mycorrhizal plants did not become mycorrhizal when inoculated with mycorrhizal roots of Centaurium.