The Island of Oahu

The Island of Oahu at one time had more endemic species of loulu than the five that are now listed:  Pritchardia ka’alae, P. kahukuensis, P. lowreyana which has recently been rediscovered on Oahu, P. martii,  and most recently P. bakeri.  Most of the species that were formerly listed were absorbed into the species Pritchardia martii.

Pritchardia ka'alae, Foster Garden, Honolulu

Pritchardia ka’alae is a rare and endangered species endemic to western Oahu where it grows at natural springs in the dry forested mountains at elevations of 1500 to 3100 feet.  The epithet is Latin for “of Ka’ala” a mountain in the Waianae Mountain range, the species native habitat.  Pritchardia ka’alae is known from scattered  populations in the central and north central  Waianae Mountains.  Five populations  are currently known to exist between Waianae Kai Haleauau summit divide and the Makua-Kea’au Ridge.  At last count, 130 individuals were noted.  These populations are located  on state and federal lands, including  Mount Ka’ala and land leased to the Department of Defense for the Makua Military Reservation.  And on Schofield Barracks Military Reservation.

This slow growing smaller species has a trunk that attains a height of 25 feet or more and a diameter of 1 foot.  The leaf crown is hemispherical or slightly more, and the leaves are semicircular, deep green on both sides with long-tipped  segments whose apices are pendulous.  A distinguishing character of the leaves are their waxy hairless or scaly surface and the thin and papery or thick and leathery physique.  This is one of the few species whose inflorescences extend beyond the leaf crown.

Pritchardia kahukuensis is endemic to the northwest end of the Ko’olau Range in the area known as Kahuku for which it is named.  It is known by its tall trunks, large spherical and full crown of leaves with drooping segment tips and infructescences with small fruit approximating the length of the leaf blades.  This species of loulu has glossy green upper leaf surfaces; the bottoms of the leaves are covered completely with a thin layer of lepidia, giving a grayish appearance.  The segments penetrate 1/3 to 1/2 of the leaf blade and sport drooping tips.  The inflorescences are composed  of a single panicle, shorter than the leaf blade and erect; the fruit cause arching and lengthening to equal or exceed the leaf blade.  The panicle branches to 2 or 3 orders and the rachillae are clothed in short, dense reddish brown hairs.  The mature fruit are 1/2 inch by 3/4 inch ellipsoid to ovoid in shape.

This loulu grows in the wet forest at an elevation of 1700 to 2000 feet.  It was once considered synonymous  with Pritchardia martii.

Pritchardia lowreyana is endemic to both the Islands of Molokai and Oahu.  Once thought to be extinct on Oahu, this species has recently been rediscovered by hikers Joel Lau and Kenji Suzuki growing on a steep north facing slope of the Ko’olau mountain range a few hundred feet below  the summit of Pu’u Ohulehule.

When first recorded in his monograph of Pritchardia in 1921, Odoardo Beccari wrote that a little known species Pritchardia macrocarpa lived in the Ko’olau Mountains on Oahu.  However, Don Hodel showed, in 2007, that Pritchardia macrocarpa was not an appropriate application of the name and suggested it be dropped.  He stated that the appropriate name for this species is Pritchardia lowreyana, which until then was known only to exist on Molokai.  More details on the species are found in the account written for the Island of Molokai.

Pritchardia martii, Foster Garden, Honolulu

Pritchardia martii is endemic to the Island of Oahu where it grows in mountainous rain forests to 3000 feet elevation.  The epithet honors the 19th Century German plant explorer Carl F.P. von Martius.  Hawaiians call this tree Loulu hiwa (dark loulu).

This palm is slow growing, short and stocky with a trunk that attains a height of 12 feet and a diameter of 1 foot (a dwarf).  The leaf crown is open and nearly spherical because of the 3 to 4 foot long, stout, felt-covered petioles.  The leaves are 3 to 4 feet wide, semicircular, broad and flat with shallow and broad, stiff segments.  Leaf color is deep olive to nearly bluish green above but silvery bronze beneath because of a dense covering of felty scales.  The fruit are small and ellipsoidal about 1 1/2 to 2 inches long by 1 to 1 1/2 inches wide narrowing at both ends.  The flower stalk grows past the ends of the leaves.  (Note the flower stalk in the photo above is shorter than the leaves; this specimen is not at the habitat elevation, though on the native  island).  Seedlings will tolerate sun from an early age and small plants are great candidates for container specimens.

Pritchardia martii, Muolea, Hana, Maui

Pritchardia martii (hastula detail), Muolea, Hana, Maui

Pritchardia martii (underleaf showing tomentum), Muolea, Hana, Maui

Pritchardia bakeri is endemic to the Island of Oahu where it is found in the Ko’olauloa District in Kahuku growing at an elevation of 1700 to 1800 feet.  This species of loulu was recently distinguished as a separate species.  The trunk grows to a height of 25 to 30 feet with a diameter of 8 to 10 inches, is mostly grayish, brownish if protected from the sun,  sports longitudinal grooves and faint leaf base scar rings.  The infructescences extend up to twice the length of the leaves, hold fruit approximately 1 1/2 inches in diameter that are dark brown to black when ripe.

Exact numbers are not known, but an estimate states that there are fewer than 250 plants occurring in the Koolau Mountains.  It is more than likely endangered and the threats are the same faced by most of the other Pritchardia species, rats, pigs and weeds, but its location in a forest reserve has the potential for protective management.

The epithet honors Ray Baker of Lyon Arboretum of the University of Hawaii in Honolulu, where he served for over 30 years.