(2007)  Page(s) 5-6.  
 
In "A Tale of Three Great Plants (and Seven Plant Collectors)" by Carolyn Jones, director/curator of the Elisabeth Carey Mill Botanical Garden, reprinted by greatplantpicks.org:
A vigorous rose, which can grow 40 to 60 feet if trained into a tall evergreen, Rosa mulliganii thrives in the maritime climate of the Pacific Northwest. This drought-tolerant rose produces large, fragrant clusters of small white flowers in early summer.

[A] rose... was growing at the Royal Horticultural Society’s (RHS) Garden at Wisley, England. This rose was of particular interest to Brian Mulligan, the Garden’s assistant director. As it did not match any species that Mulligan knew, he sent material from it to G.A. Boulenger, a Belgian botanist specializing in roses. Boulenger—who had written in three parts, between 1933 and 1936, Revision des Roses d’Asie in the Bulletin: Jardin Botanique de l’Etat Bruxelles—was well qualified to comment on this rose sent by Mulligan. Indeed, this was a new species, which Boulenger published (in the same Bulletin in 1937) and named for the sharp-eyed Mulligan. The original species description ... spelled the name Rosa mulligani. The current, correct spelling of the specific epithet is mulliganii.

Mulligan is, of course, known to all concerned with Washington Park Arboretum,for he became part of the fiber of the organization. Blessed with long life, Mulligan spent over 50 years working at the Arboretum— 26 of these as its salaried director and 24 as a volunteer, when times were tough. A quick summary of his life, for the record, completes this tale. He was born in Northern Ireland, northeast of Belfast, in 1907. He rose quickly through the horticultural ranks in Britain, obtaining a horticultural diploma from the RHS in 1933, and in 1935 he became assistant to the director at Wisley. WWII saw him balancing military duties and assisting with national vegetable-growing schemes. Recruited from Wisley to run Washington Park Arboretum, the Mulligans arrived in Seattle in late 1946. He was hired as superintendent but within five months was promoted to director. He officially retired in 1972.