Golovinomyces cynoglossi sensu lato is a powdery mildew that affects some species in the Boraginaceae, including Hound's-tongue (Cynoglossum), Borage (Borago officinalis) and Green Alkanet (Pentaglottis sempervirens); see Woods et al (2024) for more detail of hosts.  

Several similar species of Golovinomyces affect plants in the Boraginaceae

host

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Certain plants in the Boraginaceae family

In previous works, Golovinomyces cynoglossi was considered to have a wider host range within the Boraginaceae, including Comfrey (Symphytum), Forget-me-not (Myosotis) and Lungwort (Pulmonaria).  The species has now been split, and several new species of Golovinomyces have been described for these hosts - see Woods et al (2024) for more information .