Eugene Jercinovic, botanical historian, writes: "In the bottom right corner of the sheet there is a note written by Gregg including his code (1 +) [indicating the plant is 1 foot tall and in medium abundance]. The date which appears to read May 19/ 67 is almost certainly May 19/ 47 (Gregg died in 1850). Gregg's 4's are made with a single stroke and can easily be mistaken for a 6. His diary puts him near Patos, about 12 miles from Saltillo, Mexico on May 19, 1847. It seems very improbable that this specimen was collected in the United States."