In my last Post, I shared the superbloom in Anza-Borrego Desert State Park in California and some of the incredibly small plants that germinate, put a few leaves out, flower, fruit, and die—all in a matter of weeks. Today, I continue the theme of minute plants, this time in the Arnold Arboretum. With seeds collected from around the northern hemisphere and on the grounds of the Arboretum, the propagation greenhouses are now the site of incredible energy and beauty. Flat after flat of future trees are germinating.
Top image, seedlings of the Japanese lime tree (Tilia kiusiana) collected on the grounds of the Arboretum. The two seedling leaves (cotyledons) on each plant are very unusual, in that they are palmate (think of the first pair of leaves on your cucumber or tomato seedlings for comparison―ovoid or lanceolate). Totally weird, but wonderful. Lower left, Caucasian or Oriental spruce (Picea orientalis), collected in Borjom-Kharagauli National Park on the 2016 Arnold Arboretum collecting expedition to the Republic of Georgia.
Finally, seedlings of the California cypress (Hesperocyparis goveniana) from the pygmy forest in Salt Point State Park in California. This amazing patch of forest, with entirely dwarfed forms of trees, results from a combination of brutal hardpan soils and low nutrient availability. While most of the minute seedlings in the propagation greenhouses will eventually ascend to great heights on the grounds of the Arnold Arboretum, these pygmy cypress seedlings are destined for the bonsai and penjing collection. They are perfectly pre-adapted!