Rubus hawaiensis

Taxobox
name = "Rubus hawaiensis"

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image_width = 240px
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Rosales
familia = Rosaceae
genus = "Rubus"
species = "R. hawaiensis"
binomial = "Rubus hawaiensis"
binomial_authority = A. Gray.

"Rubus hawaiensis" (Hawaiian: "okinaākala") is a species of "Rubus" endemic to Hawaiokinai. The native Hawaiian name is okinaākala. It is found throughout the Hawaiian Islands in mesic to wet forest, typically at mid to upper elevations (above 600 m). In most areas it is not very common, but in some places (such as the upper Kookinaolau Gap in Haleakalā and Laupāhoehoe Natural Area Reserve) it can be a dominant member of the understory vegetation. Although superficially similar to the other Hawaiian species, "Rubus macraei", the two are believed to be derived from separate introductions to Hawaiokinai.

"Rubus hawaiensis" is a deciduous shrub, typically growing as a clump of erect or (when longer) arching canes, 1.5-3 m long. The leaves are compound, with three leaflets. The fruit is red, large (up to 4 cm long and 2.5 cm wide), and edible but not often eaten, as it is sour and somewhat bitter.

Although frequently described as thornless (and often used as an example of loss of defenses in island plants), most plants do have thin thorns (which can make splinters and be quite painful) at least when small. As the cane grows the outer layer of bark usually sheds, taking the thorns with it. Interest in breeding thornless varieties of edible raspberries (possibly even with distantly related species since most "Rubus" readily hybridize) has led to the introduction of several species of continental "Rubus" species which have since escaped cultivation and become serious pests. These include the yellow Himalayan raspberry, "Rubus ellipticus", and the Florida prickly blackberry, "Rubus penetrans". Both of these are odd choices for breeding for cultivation as they have small, poor-tasting fruit.

The presence of highly damaging alien "Rubus" species along with a native species has led to a debate on biological control. Specifically, whether an agent that might be able to control the alien species (which are highly invasive in native forest and crowd out native species) should be released even if it may have serious impacts on a native species, if the latter is (like the ʻākala) not part of a major evolutionary diversification and not a major part of most ecosystems. Some would argue that it is worth sacrificing a small component in order to save the whole ecosystem, while others say that humans should not be multiplying the damage they have already caused by introducing the aliens.

External links

* [http://www.botany.hawaii.edu/faculty/carr/rubus.htm Hawaiian Native Plant Genera - Rubus] Photographs of "R. hawaiensis".