This may be correctly identified as Echinopsis 'L.A.', or perhaps it lingers as one of the mysterious fore-runners of Echinopsis 'L.A.'mentioned in some of the older literature on echinopsis hybrids. I received this plant as a gift in 1976, and have delighted in its large, 'Easter Lily Cactus' flowers with their jasmine & citrus fragrance ever since.
Britton & Rose attribute the name 'gemmata' to Schumann in Martius, Fl. Brazil in 1890, but list the parent plant under Echinopsis turbinata in "The Cactaceae". Closer reading under this heading in B&R finds mention of a Echinopsis schelhasie rosea Rumpler [Forster, Handbook of Cacti, 2nd Edition, 1885]. Rumpler also describes Echinopsis decaisneanaas under the same B&R entry, as 'a delicately fragrant, beautiful pink form with large flowers; the inner perianth-segments long, acute or acuminate. It is a hybrid between this and some other species. The flowers open during the day and last usually for more than one day."
Although the specimen shown is being grown in a large pot in the greenhouse keeping all but two offsets removed, outdoors the plant offsets merrily into grand clusters that carry many flowers at once in spring, and blooms less vigorously during summer and early fall months.