Umbellifer: “The Swallowtail of June 1906 was still in the larval stage on a roadside umbellifer.”
Plants of the order Umbelliferæ, possessing umbellate flowers. Carrots, parsley, dill and fennel are umbellifers, each with an inflorescence of short flower stalks called pedicels, radiating from a central point like the spokes of an umbrella. Nicely, the OED’s first citation for the adjective form is from the naturalist John Ray’s Select Remains (1705): “I observed, creeping upon the Ground, a small umbelliferous Plant.” The foreword to Lolita is attributed to the fictional John Ray Jr., Ph. D.
Purl: “When that pearly language of hers purled and scintillated.”
The OED gives my favorite etymology: “Origin uncertain.” As a noun, in knitting it means a “stitch which is the inverse of the knit stitch.” In a joke that’s probably incomprehensible today, Steve Allen used to say: “Knit one, Purl Bailey.” As a verb, it carries over its meaning from knitting and lacework, but here is the sense Nabokov probably intended: “To utter with a soft, murmuring sound.” The sound is the sense. Purl: a lovely word.
Lambency: “I had nothing—except one token light in the potentially refulgent [another choice word] chandelier of Mademoiselle’s bedroom, whose door, by our family doctor’s decree (I salute you Dr. Sokolov!), remained slightly ajar. Its vertical line of lambency (which a child’s tears could transform into dazzling rays of compassion) was something I could cling to, since in absolute darkness my head would swim and my mind melt in a travesty of the death struggle.”
In phonetic terms, a word beginning with a lovely alveolar lateral approximant, meaning “being lambent or shining with a clear soft light like a flame.” In Modern Painters, Ruskin gives us: “The soft lambency of the streamlet.” The OED offers a rare derivative usage: “brilliance and delicate play of wit or fancy,” and cites a writer, Robert Louis Stevenson (from Prince Otto: A Romance, 1885), much admired by Nabokov: “A man of great erudition and some lambencies of wit.”
Stevenson’s phrase fits my old acquaintance pretty well, especially when lambencies of wit usurped his Midwestern earnestness.