Today we celebrate an English botanist who discovered which way sap flows in plants. We'll also learn about a female Dutch botanist who fought for equity and is now remembered as a trailblazer. We’ll remember a thoughtful and witty garden writer whose only book became a garden classic. We hear some thoughts on the garden in winter from one of my favorite authors. We Grow That Garden Library™ with a book that shares the story of the French naturalist and medical doctor Aimé Bonpland (“bon-plon”). And then we’ll wrap things up with a little garden trivia in honor of National Trivia Day.   Subscribe Apple | Google | Spotify | Stitcher | iHeart To listen to the show while you're at home, just ask Alexa or Google to “Play the latest episode of The Daily Gardener Podcast.” And she will. It's just that easy.   The Daily Gardener Friday Newsletter Sign up for the FREE Friday Newsletter featuring: A personal update from me Garden-related items for your calendar The Grow That Garden Library™ featured books for the week Gardener gift ideas Garden-inspired recipes Exclusive updates regarding the show Plus, each week, one lucky subscriber wins a book from the Grow That Garden Library™ bookshelf.   Gardener Greetings Send your garden pics, stories, birthday wishes, and so forth to Jennifer@theDailyGardener.org   Curated News Invasive Species Spotlight: Garlic Mustard | Washington Gardener | Jacqueline Hyman   Facebook Group If you'd like to check out my curated news articles and original blog posts for yourself, you're in luck. I share all of it with the Listener Community in the Free Facebook Group - The Daily Gardener Community. So, there’s no need to take notes or search for links. The next time you're on Facebook, search for Daily Gardener Community where you’d search for a friend... and request to join. I'd love to meet you in the group.   Important Events January 4, 1761 Today is the anniversary of the death of the English clergyman, botanist, and physiologist Stephen Hales. Stephen applied himself to many different areas of science. Stephen spent most of his life studying tree sap and blood flow. Do you know the direction sap flows in a plant? Stephen figured this out - it flows upward - and he also examined other fascinating aspects of plants like the sap's pressure, the pressure roots exert on sap, and how fast shoots and leaves grow. He also demonstrated that plants absorb air. Stephen’s curiosity about sap and blood flow led him to become the first person to measure blood flow, blood volume, and blood pressure. Stephen was always thinking about the forces around us - from our internal blood pressure to external air pressure. It’s not surprising that Stephen became curious about air quality and whether improved airflow could help fight typhus. And so, Stephen invented a ventilator to purify stale air. Stephen’s device was essentially large bellows that had to be moved by hand, but they were still effective and were used in ships, prisons, and mines. And there was another use for Stephen’s ventilator: it also preserved and dried food. In the twilight of his life, Stephen had royal visitors. Frederick, Prince of Wales, and his wife, Princess Augusta, both stopped by to discuss gardening and botany. And it was Stephen Hales who gave Princess Augusta advice on the creation of Kew Gardens. Today, Stephen is remembered in the genus for the snowdrop tree, the Halesia carolina. And since 1927, the Stephen Hales Prize is awarded to a scientist who made an outstanding contribution to plant biology science.   January 4, 1883 Today is the birthday of a Dutch plant pathologist and the first female professor in the Netherlands, Johanna Westerdijk, who went by "Hans." In 1906, Johanna completed her thesis on the regeneration of mosses, and she was hired to be the director of a major botanical institute at the ripe old age of 23. By 1917, Johanna became the first female professor in the Netherlands. During her tenure, Johanna supervised 56 d