| Layers | Rate of growth. | |||
| Counted on it | 1,500 | First century | 10¼ | in. radius |
| Uncounted sapwood (est.) | 30 | “ 400 years | 27¼ | “ “ |
| “ centre “ | 10 | Last century | 3½ | “ “ |
| Growth to 21 feet “ | 10 | Last 400 years | 14 | “ “ |
| Estimated age (years) | 1550 | |||
[31] First Lessons in Botany.
[32] Isaac F. Holton, M. D., 1813-1874; teacher and professor of natural science in Vermont, and missionary pastor in Illinois. Published in 1857 New Granada, Twenty Months in the Andes.
[33] A Journey in the Seaboard Slave States, with Remarks on their Economy. By Frederic Law Olmsted. New York, 1856.
[34] William Darlington, M. D., 1782-1863, of West Chester, Penn.; author of Flora Cestrica, “one of the best of local Floras,” and Memorials of Bartram and Marshall, etc. “A most faithful botanist. His forte was the clear and accurate description of plants” [A. G.].
[35] Thomas Potts James, 1804-1882. Born in Radnor, Penn. A proficient and authority in bryology.
[36] First Lessons.
[37] How Plants Grow. Sir Joseph Hooker in Nature, February 16, 1888, says of How Plants Grow and How Plants Behave, “that for charm of matter and style they have no equal in botanical literature.”
[38] Daniel Cady Eaton, professor of botany at Yale.
[39] Botanical Gazette, March, 1888.