Article from Bean's Trees and Shrubs Hardy in the British Isles
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'Cotoneaster integerrimus' from the website Trees and Shrubs Online (treesandshrubsonline.
A deciduous shrub 4 to 7 ft high, of rounded, bushy habit; young wood woolly. Leaves 3⁄4 to 11⁄2 in. long, varying in outline from broadly ovate to almost round; sometimes pointed, sometimes rounded at the apex; glabrous or nearly so above, always densely grey-felted beneath; stalk 1⁄4 in. or less long. Flowers white, rose-tinted, produced two to four together in short nodding clusters. Fruit round, 1⁄4 in. across, red; nutlets two.
Native of Europe and N. Asia, and interesting as the only cotoneaster truly native of Britain. In 1783 it was discovered on the cliffs of Great Orme’s Head, near Llandudno, by J. W. Griffith. This appears to be its only habitat in the British Isles, and even there it is now reduced to very few plants. I have spent a good deal of time wandering over the Head, but have never seen it there. (It has been seen in one or two places since these words were written but is now extremely rare. The latest specimen from this area in the Kew Herbarium is dated 1941.) The species flowers in April and May, but has little garden value. From its ally C. tomentosus, this differs in its glabrous calyx.