Mycorrhizas of the Liliiflorae

Summary Vesicular–arbuscular mycorrhizal (VAM) infections were examined in 30 cultivars of Narcissus L., Tulipa L. and Crocus L. over a period of 2 years. There was considerable diversity in the morphology of the VAM infections amongst, and variation of levels within, different genera. The possible causes of these variations, such as high levels of soluble phosphorus and host repression of the VAM endophytes, are discussed. Seven endophytes were identified from spore morphology. No apparent relationship existed between level of VAM and spore numbers in the field. Tulipa and Crocus roots were devoid of root‐hairs. Analysis of the incidence of root hairs in relation to VAM infection in Narcissus suggested that mycorrhizas were significantly less likely to bear root hairs.