Haleakalā Silversword, ʻAhinahina
Argyroxiphium sandwicense subsp. macrocephalum

I received a gentle nudge from a subscriber that a blog post was overdue. Thanks for your interest. I have chosen a subject that I have been thinking about for awhile, but which I am at a loss at where to start. This is because a blog cannot do this plant justice. But here it goes.

The Haleakalā silversword, named by Hawaiians as ‘ahinahina, has an incredible story. There has been a considerable amount of research on this native plant, which is only endemic to the upper slopes of Haleakalā, a volcanic mountain on Maui with an elevation of 10,000 ft. In other words, the ‘ahinahina is not endemic to any of the other islands in the Hawaiian chain.

The ‘ahinahina belongs to a group of approximately 30 related plants in what is called the Silversword Alliance. Exactly how an ancestor to plants in the Alliance came to the islands will never be proven. However, scientists now believe that a seed hitched a ride to the islands on a bird, and more interestingly, botanists have identified the family of the traveling seed.

First, I would like to acknowledge all the scientists and botanists who contributed to this research, as I am sure there were many who spent countless hours doing mind-numbing work. However, I would like to name a few of the botanists most noted for their research on this topic and leave it up to my dear subscribers to identify the others.

In the 1800s, a botanist named Asa Gray was the first to make a connection between sunflowers and silverswords, putting them together in the tribe Madiinae in plant taxonomy. Then years later in 1953, a young botanist named Sherwin Carlquist was hiking in Haleakalā crater and immediately recognized similarities between the ‘ahinahina and the California tarweed, the latter which belongs to the sunflower family. He researched this further and his findings supported his intuition. However, his beliefs regarding long-distance seed dispersal and the relationship between the tarweeds and silverswords were controversial at the time and not well-received by some of his peers. Indeed, at first glance, these two plants do not look similar to each other and you might not make the connection unless you are as astute as Sherwin Carlquist was.

With significant interest in how plants evolved in Hawaii, partly due to the young age of the islands and long distance from other land masses, botanists continued to research plants in the Silversword Alliance. Finally, after decades of conflicting opinions, professor Bruce G. Baldwin of U. C. Berkeley spearheaded DNA research that supported Carlquist’s theory. Much of the publications are very technical. I even attempted to read the book “Tarweeds & Silverswords: Evolution of the Madiinae (Asteraceae)”, written by Sherwin Carlquist, Bruce Baldwin and Gerald Carr. I managed to get through the first chapters which were very interesting and I especially liked the family tree diagrams. The book is written for botanists and is filled with technical data. I was hoping to see more photos, but I suppose that is my job. As I understand, the botanists concluded that an ancestor to the California or North American tarweed was an ancestor to plants in the Silversword Alliance. In other words, these tarweeds and silverswords descended from a common ancestor. Asa Gray and especially Sherwin Carlquist were correct all along, but it took modern technology to support their conclusions.

As I mentioned earlier, the story of the ‘ahinahina cannot be told in a single blog. Therefore, I will end here and continue with more interesting details in another blog or two. I almost forgot that this blog about photography. If you look closely at the photo above, you might see the resemblance of the ‘ahinahina to sunflowers.

p.s. If any botanists out there have new information to share about the ‘ahinahina, feel free to send updates via the Contact form and include links to reliable sources.