Implemented by: Henrietta Myburg and Marc JohnsonThis protocol is a modification of protocol 8. It was developed after protocol 8 and several commercially available plant RNA isolation kits failed to produce a sufficient yield and quality of RNA from Oenothera spp. (Onagraceae) for next-generation sequencing. Oenothera are rich in polysaccharides, oils, flavonoids and complex ellagitannins that likely interfere with isolation.We suspect that this protocol will be most useful for species and tissues with complex secondarychemistry and rich in oils (e.g. some Rosaceae and Pinaceae). The most important modifications to this protocol versus Protocol 8 is the use of less plant tissue, more extraction buffer, and repeating solvent extractions until the interphase is clean of debris. The protocol is regrettably longer and more involved than Protocol 8. We attempted to remove or reduce the replication of the solvent extractions steps without success (i.e. yield and quality are always decreased in Oenothera when any steps are removed).This protocol is part of a collection of eighteen protocols used to isolate total RNA from plant tissue. (RNA Isolation from Plant Tissue Collection: https://www.protocols.io/view/rna-isolation-from-plant-tissue-439gyr6)