Botany Photo of the Day

The unfurling fronds of Western maidenhair fern in dim, morning light look little like the mature fronds in indirect sunlight.

The distribution of Adiantum aleuticum (map) is a case study in disjunct populations, or populations of a species separated by a wide geographic or ecological distance. Broadly speaking, western maidenhair fern's main distribution range is coastal and inland forests of Alaska south to California. However, as mentioned by the Flora of North America account for the species, it is also “disjunct in wet rock fissures at high elevations in Arizona, Colorado, Montana, Nevada, Utah, Wyoming, and Mexico in Chihuahua, and it is disjunct on serpentine in Newfoundland, Quebec, Maine, Maryland, Pennsylvania, and Vermont.” Your task of the day is to generate a possible explanation for the pattern of this plant's distribution, particularly for its disjunct populations (the map link above gives a clear overview of the distribution).

Landscape architecture / horticulture resource link: Dr. Peter Del Tredici from Harvard University's Arnold Arboretum has two articles worth reading in the February 2006 issue of Landscape Architecture. The first, titled “Because Plants Are At Stake” (PDF), addresses the importance of having a knowledge of plants in the field of landscape architecture. The second, “Brave New Ecology (PDF)”, tackles the question “Can we ever put the invasive species genie back in the bottle, or are we looking at a future in which nature as we know it becomes a cultivated entity?”