While the northeast is blanketed in snow and ice, even in Cambridge, Massachusetts, amazing flowers made of glass are blooming at the Harvard Museum of Natural History. In a darkened room on the third floor of the museum, glass cases sparkle, carefully lit to best show off grasses with their seed heads, delicate wildflowers, cocao plant and seed, one of the economically important plants on display, and more familiar flowers like rhododendron, mountain laurel, iris and dahlia. Each…