Amsonia hirtella
Maricopa Co., AZ
Spjut 3311, 23 April 1973

Amsonia hirtella
Maricopa Co., Tortilla Creek, AZ
27 May 1965, Barr 65-228

Amsonia tomentosa
E San Bernardino Co., CA
Spjut 15256, May 2003

Amsonia tomentosa
E San Bernardino Co.,, CA
Spjut 15255, May 2003

Amsonia tomentosa
E San Bernardino Co., CA
May 1978

Furmanowa M and L. Rapczewska.  1977. Amsonia tabernaemontana Walter (Apocynaceae) in tissue culture—growth and alkaloid production. Acta. Pol. Pharm. 34(2): 215–219.

Morin H.,  J. Lemen and H. Pourrat.  1955.  Pharmacodynamic study of tabersonine, an alkaloid extracted from the seeds of Amsonia tabernaemontana Walt. (Apocyanaceae).
Ann. Pharm. Fr. 13(2): 123–126. In French.

Panas J. M., A.  M. Morfaux, L. Olivier and J. Le Men. 1972.  Alkaloids of leaves of Amsonia tabernoemontana Walt., Apocynaceae.  Ann. Pharm. Fr. 30(4):273-276. In French.

Zabolotnaia E. S.,  A. S. Belikov, S. P. Ivashchenko and M. M.  Molodozhnikov.  1964.  Alkaloids of Amsonia tabernaemontana Walt. Med. Prom. SSSR. 18: 28–29. In Russian..

Zsadon B., L. Decsei, K. Otta, M. Szilasi and P. Kaposi. 1974.  Isolation of aspidosperma alkaloids and rutin from Amsonia tabernaemontana Walt. Acta Pharm. Hung. Jun suppl 1: 74–79. In Hungarian.