Lobelias at Puu Kaaumakua

Posted: December 7, 2008

When I read Patrick Rorie’s report that lobelias were flowering at the summit of Pu’u Ka’aumakua, I had to see these flowers with my own eyes to learn which species of lobelia was in bloom.

Puu Kaaumakua is the 2,681 foot peak on the Ko’olau Mountains which towers over the valleys of Kahana and Waikane on the Windard side and overlooks Kipapa on the leeward side. I took the same 11-mile round trip to the summit taken by Patrick which starts in Waikane Valley.

After parking at the junction of Kamehameha Highway and Waikane Valley Road, I started up the paved road and then veered-off onto the dirt road that leads to the back of Waikane Valley. When I reached Waikane Stream I splashed in the cool refreshing waters for a bit before proceeding to the back of the valley.

Ferns and mosses thrive along the sides of the road which services the tunnels and ditches that are part of the Waiahole Ditch System.

Based on a ruling by the Supreme Court of Hawaii, much of the water in Waikane Stream is derived from a tunnel bored into the mountain-side which taps the aquifer. Click here to learn more about the legal battles that were waged over the water.

Yellow ginger overlooks the stream as it crosses over the road and then falls back into the streambed. I continued around the bend in the road which leads to a covered ditch and tunnel which is hidden but gives itself away by the sound of running water. The trail that contours along the back of Waikane and climbs to Pu’u Ka’aumakua starts at this covered ditch and tunnel.

Proceeding along the contour trail, I turned the corner out of Waikane Valley and entered the back of Kahana Valley. Thanks to the trail maintenance crew of the Hawaiian Trail and Mountain Club who cleared the trail several weeks earlier, the trail was wide open and easy to negotiate.

One of the more pleasant sights along the way was a thriving ha’iwale (cyrtandra calpidicapra) shrub along the trail. This particular species is not endangered although nine cyrantandra species are on the list of endangered species. In any event, cyrtandras are not a common sight on Oahu.

The trail contours up the side of Koolau mountains at a nice grade and connects with the Koolau Summit Trail (KST) in the very back of Kahana Valley. The ohia lehua trees along this section of the Ko’olau are often shrouded in clouds and grow as short shrubs covered with green and brown mosses.

Clouds blew in and covered the Ko’olau summit ridge as I made my way up the trail. Large loulu palms (Pritchardia martii) along trail were enveloped in a fine mist.

When I reached the top of Pu’u Ka’aumakua, clouds completed shrouded the summit. I was pleased to see several lobelias growing from moss-covered mounds. The lobelias at the summit are koli’i (Trematolobelia macrostachys) which are also found on the summit of Mount Ka’ala on the Waianae Mountains and at Poamoho about 5 miles further north along the Ko’olau Summit Trail. Koli’i are not on the list of endangered species but are not a common sight on Oahu.

Just as Patrick reported, one of the koli’i at the summit was in bloom with pink and white flowers. The inflorescence had 8 flower stalks each about 7 inches long emanating from the center of the plant like the spokes of a wheel.

Each of the 8 flower stalks had over 2 dozen buds which opened a handful at a time starting from the end of the stalk closest to the center of the plant and then working their way towards the periphery.

Koli’i flowers, which are just under 2 inches long, open-up in two stages in order to prevent the flowers from self-pollinating themselves.

When the flowers initially open pollen is produced from the white bristly stamens at the very tip of the flowers. After a few days the stamens fall off and are replaced by a greenish-yellow bulbous stigma at tip of the flower which must be pollinated in order for seeds to develop.

After photographing the koli’i at the summit Pu’u Ka’aumakua, I turned around to descend the way I came. As I made my way down to the junction with the KST, the clouds lifted and provided spectacular views of Kahana Valley and Pu’u Ohulehule.

One of the more charming sights were lehua blossoms covered with dew — otherwise known as “kanoe lehua”. Moisture from passing clouds had condensed on the stamens and pistils of the flower.

When I turned the corner to exit Kahana Valley, the sun illuminated Ohulehule, Waikane Valley, and Kaneohe Bay. Except for a good-sized pig that startled me as I made my way down the very back of Waikane Valley — I made my way out without incident. As I reached my car and drove back home, I reflected on my hike and was pleased to have climbed to the summit of Pu’u Kaaumakua to see the koli’i. Many thanks to Patrick for the most excellent tip.

–

SOURCES

Hawaii’s Endangered Plants, Bishop Museum

Plants in the Campanulaeae “Lobelia” Family on Oahu, Complied by Ken (Kenji) Suzuki, 2006

Pure Cyrtandra Species Found on Oahu, Complied by Ken (Kenji) Suzuki, 2005

3 Responses to “Lobelias at Puu Kaaumakua”

Met Lebar says:

December 6, 2008 at 6:46 pm

Hi Nathan,
great photos and a very educational wtiteup. I always love to learn about plants and Hawaiiana from your site.

Mahalo,
Met
Nathan Yuen says:

December 7, 2008 at 8:03 pm

Glad you enjoy the photos. I too learn a lot researching the subject before writing the write-up.
Hawaii flowers, rainforest plants, and hidden Hawaii through fine art nature photography says:

October 9, 2009 at 8:10 pm

[...] and Trematolobeia macrostachys (the species of lobelia on Puu Kaaumakua and Mount Kaala) is that macrostachys has 8 flower stalks which emanate from the center of the plant like the spokes of a wheel, while [...]

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Lobelias at Puu Kaaumakua

Posted: December 7, 2008

3 Responses to “Lobelias at Puu Kaaumakua”

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