This impressive collection of original artwork is by leading botanical illustrator and lithographer J.L. Macfarlane FRHS (1836–c.1913). Scottish-born Macfarlane trained at Paisley Art School before making his career in London and becoming one of the earliest of the painters employed by the RHS to depict prize-winning orchids. He did many plates for nurserymen, notably William Bull, Thomas Cripps and B.S. Williams, as well as contributing to various horticultural journals such as 'The Florist and Pomologist'.

Many of the illustrations in the collection are of pelargoniums—flowers which are often misnamed and mistaken for geraniums, a point of confusion which was commonly discussed in gardening publications of the late 19th-century. There are around 17,000 pelargonium cultivars, and Macfarlane's large paintings show off a number of these in all their vibrant glory. Nurseryman William Bull specialised in pelargoniums, so it is likely these illustrations relate to plates for one of Bull's catalogues, in which the seedman introduced his new cultivars. Throughout the 19th century, the qualities most prized in pelargoniums were broad, round petals, clear in colour—evident in these full and crisply executed watercolours, almost luminous in their pure colour, intensified with gum arabic.

In 1876 William Bull introduced the name 'Regal' in his catalogue of 'New Beautiful and Rare Plants' which was 'applied to that magnificent group of Pelargoniums, the flowers of which are of large size, very rich and showy, and although they are not really double, yet from their fullness of form and extra number of petals, they have the appearance of being so.' There are a number of such flowers illustrated in this collection. Most paintings have their specific cultivar name inscribed on the verso, a number of which are royal. Some have annotations of a price per dozen.

It has also been suggested that these paintings were illustrations for The Garden: An Illustrated Weekly Journal of Horticulture in All its Branches, founded by William Robinson in 1871. Robinson was a prolific garden writer who disliked artificiality and spurred the movement that led to the popularising of the English cottage garden, an ethos which paralleled the search for an honest and authentic vernacular style of the Arts and Crafts movement. 'The Garden' publication included large coloured plate illustrations, punctuated Robinson's prodigious text.

Above all, these paintings evoke a Victorian golden age of horticulture—a time when nurserymen were household names and glasshouses could exceed twenty acres. The rise of a new middle class and an explosion in house building created a hungry market for the nursery industry, which grew rapidly to meet the demand for ornamental plants. The era's botanical illustrations survive as evidence of the endeavour to navigate and record this developing science.

There is one hand-coloured lithograph in the collection which is signed 'J.L.M. in the plate and lettered 'J.L. Macfarlane del et Lith'.