Sentence:  [...] the amended <WSD>yearday</WSD> which was the middle day in flowering range. the <WSD>yearday</WSD> which is equivalent to commencement of flowering. the amended <WSD>yearday</WSD> (based on flowering <WSD>yearday</WSD>) which is the equivalent to the commencement of [...] 
Meaning of the word marked with <WSD> tags:  A day or time occurring in a yearly cycle; an annual day, season, or event.