This gray Sunday I am alternating between a view of the swirling snow and my Christmas book Latin for Gardeners: Over 3000 Plant Names Explained and Explored. by Lorraine Harrison.  I never took Latin in school but over the years, almost in spite of myself, I have picked up a fair amount of horticultureal Latin. I don't always remember the Latin names of the plants in my garden, but knowing some Latin has given me information about plants…