The Flowering Plants of Hawaii
Part 15 Cuscutaceae - Droseraceae - Ebenaceae - Elaeagnaceae
Cuscuta is the only genus in Cuscutaceae, known most commonly as the dodder family. Some authorities prefer to include Cuscuta with the morning glories in Convolvulaceae (Soltis et al., 2005; Mabberley, p. 240) but we’ll keep with the Manual in following the traditional taxonomy in this series. Two species of dodder—there are about 150 in this cosmopolitan genus—occur in the islands, C. campestris, the common western field dodder native to western North America, and the Hawaiian endemic C. sandwichiana (see images). The mainland dodder prefers legumes as host, whereas the Hawaiian species appears to have no preference for host-plant having been found to parasitize any plant it encounters; the darker pigmented dodder was attached firmly to a species of Heliotropium.; the paler colored plant appeared to be associated with seagrape (Cocoloba uvivera, Polygonaceae). Ever resourceful, Hawaiian lei makers utilize the sticky nature of dodder in making their lei haku, or braided strand leis.
Droseraceae, the sundew family, are a group of carnivorous plants that grow in wet nitrogen-poor locales that get their required nitrogen from the insects that land on their attractive, sticky leaves. The Hawaiian member of this family, Drosera anglica (see image), mikinalo in Hawaiian, occurs in high elevation bogs of Kaua`i and in bogs in the Northern hemisphere. Authors of the Manual suggest this plant might have arrived on the islands via seeds imbedded in mud on the feet of migrating birds.
Ebenaceae, the ebony or persimmon family, are a family of tropical and subtropical hardwoods, represented in the Hawaiian Islands by two endemic species of Diospyros. The term ‘ebony’ refers in general to species of Diospyros, but, as is the case with many common names, it has been used in reference to other hardwood trees. The family is a moderately large one, 400 species according to the Manual, 575 according to Mabberley (p. 277) sorted into three genera (Euclea and Lissocarpa are the other two). There has been some rearrangement within the family as evidenced by the difference in number of genera recognized, five according to the Manual, only the three according to the later source. The two Hawaiian species of Diospyros are D. hillebrandii from Kaua`i and O`ahu, and D. sandwicensis, which occurs on all of the main islands. Hawaiians have two names for Diospyros, lama and ëlama.
Diospyros sandwicensis (see images), a species native to dry to mesic forests on all of the main islands, except Ni`ihau and Kaho`olawe. The photograph of this species was taken in the dry forest on western Läna`i, where it contributes about 20% of the hardwood trees to this unique forest. The yellow to orange fruit of this persimmon eaten directly from the tree is quite flavorful.
Elaeagnus umbellata, an Asian native that has been cultivated on the islands, has escaped and is spreading in disturbed ground near Volcano Village and the Kilauea Volcano area. Whether it presents a potential problem remains to be seen. It has been reported that a single plant can produce up to 200,000 seeds per year. Distribution is primarily by birds who are attracted by the fleshy, red fruit. I do not have a photograph of E. umbellate so I have included an illustration of the bright red fruit of related E. multiflora (see image) which clearly shows the attractive fruits.
Additions to the list of families:
The Addendum to the Manual includes members of two families that have only recently been recognized as having become naturalized on the islands. The families are Dilleniaceae and Dipsacaceae. Dilleniaceae are an Australasian family of 300 species in 13 genera one of which is of interest to us here. Dillenia indica, commonly known as elephant apple or simpoh, can be found growing in the Enchanting Floral Garden and in the Kahanu Gardens (NTBG), both on Maui. An image of D. indica from the Starr collection is included (see image).
The second newly naturalized species is Scabiosa palaeshina which was historically a member of Dipsacaceae (Dipsacus sativus is the common teasel) but is now considered to belong in Caprifoliaceae. I have no further information on this plant in the islands other than it was found growing on O`ahu. Members of this genus are popular decorative plants which suggests that it has escaped from cultivation.
January 30, 2012