My dear M^r Darwin

My impression is certainly ⁠⟨⁠1 word missing⁠⟩⁠ strong that plants with a smooth glauc⁠⟨⁠ous⁠⟩⁠ epidermis to their foliage and branches are chiefly prevalent in hot dry situations— in the Mediterranean region in Australia in South Africa in the dry parts of Mexico—in plants that grow in exposed rocky sunny situations—in apricis et maritimis—and are rare in moist climates in rich soils—² The Eucalypti and Phyllodineus³Acacias of Australia the Mexican Cacti the Mediterranean Caryophylleae e.g. Gypsophila and Cruciferae⁴ and many others show a large proportion of glaucous plants, but the case may ⁠⟨⁠2 or 3 words missing⁠⟩⁠ ⁠⟨⁠w⁠⟩⁠ith the fugacious bloom ⁠⟨⁠1 or 2 words missing⁠⟩⁠ ⁠⟨⁠ ⁠⟩⁠ch as plums grapes etc   Olive⁠⟨⁠r⁠⟩⁠⁵ tells me that this bloom has been the subject of researches of some of the German physiologists and refers me to de Barys elaborate paper in Mohl’s Botanische Zeitung 1871, 128, 145, 161, 566, 593 589, 605—but this you are probably acquainted with.⁶

It has always appeared to me that similar hot exposed situtations tend to the development of rigid hairs and cottony wool—much more abundant in species or varieties belonging to such situations than in those grown in moist rich ones

Yours very sincerely | George Bentham