Very flowery language, and no definitive meaning! Could imply that they are simple (ie basic), or not very good (base as in the bottom of something, thus lowest). If she's talking about what she wrote in her autobiography, then saying her choice of words was "bulbous" really is nonsense (if poetic). She might mean the phrases were rather long, rather than short and precise, and "materiality" could mean they were somewhat concrete descriptions rather than looser and less precise. No idea who wrote this, but good luck with such abstruse English! Dangerously close to Alice in Wonderland, where Humpty Dumpty says "words mean exactly what I want them to mean"!!!