Publications:

Sampson, D. A. and R. A. Krebs. 2012. Quantitative evaluation of reciprocal herkogamy in the distylous species, Hedyotis caerulea (Rubiaeceae). Plant Systematics and Evolution 298: 1361-1370.

Sampson, D. A. and R. A. Krebs. Developmental variation and distyly in Hedyotis caerulea (Rubiaceae). SpringPlus  DOI: 10.1186/10.1186/2193-1801-2-383 URL: http://www.springerplus.com/content/2/1/383