Plants of Midway Atoll

Approximately 249 plant taxa have been reported on Midway from the time it was first discovered through 1992. Of these, 119 taxa were known only from cultivation, 104 taxa had become naturalized from either intentional or accidental introductions, and 24 taxa were native to Midway.

The most common and in most cases, invasive/noxious, introduced taxa include Ironwood (Casuarina equisetifolia), Golden crown-beard (Verbesina enceloides), Wild poinsettia (Euphorbia cyanospora), Haole koa (Leucaena leucocephala), Sweet alyssum (Lobularia maritima), Buffalo grass (Stenotaphrum secundatum), Peppergrass (Lepidium virginicum), and Bermuda grass (Cynodon dactylon).

Fifteen of the native taxa are indigenous, or found elsewhere beyond the Hawaiian Islands, and nine are endemic to the Hawaiian Islands. None of the endemic taxa are restricted to Midway Atoll (Wagner et al. 1990). Native Plants on Midway Atoll NWR brochure (pdf - 516k)

Below is the list of Midway Atoll's common indigenous plants.

Scaevola sericea

Indigenous. Perennial. Shrubs usually grow clumped close to the ground, but can grow up to 3 m tall. Leaves simple, alternate, crowded at stem tips, blades fleshy and succulent, surfaces glossy. Flowers several, in short axillary cymes. Corolla white to pale yellow. Split along one side and 5-lobed. Fruit a fleshy white, subglobose drupe, tolerant of salt water and buoyant, thus easily dispersed, moving along with the currents and tides around the tropical portions of the Pacific Basin.

On Midway, naupaka flowers from July through November. Fruits appear by mid-August, with an abundance in September. Some fruits can be found in December.

Occurring throughout tropical and subtropical Pacific and Indian Ocean coasts; found on all the major archipelagoes of Polynesia and Micronesia. In Hawaii, common in coastal sites throughout the Hawaiian Archipelago, except Gardner Pinnacles, Necker, and Nihoa. One of the most common littoral shrubs, often forming dense thickets on rocky and sandy coasts.

Tournefortia argentea

Introduced and naturalized. Small tree up to 5 m or more in height. Leaves simple, alternate and appearing whorled at branch tips. Blade fleshy, 10-20 cm long, densely silky pubescent (covered with soft hair) on both surfaces. Flowers sessile (lacking stalk) in stiff, widely branching. Calyx deeply divided about halfway into 5 elliptical lobes. Fruits white to green, globose, 3-6 mm long, ultimately dividing into four nutlets. Native to tropical Asia, Madagascar, tropical Australia, Tuamotus, and most of the low and high islands of Micronesia and Polynesia. A modern introduction to Hawaii. Tournefortia has become naturalized and relatively common in coastal areas on Kure, Midway, and Pearl and Hermes Atolls; Lisianski and Laysan Islands; French Frigate Shoals; and all of the main Hawaiian islands, except Kaho'olawe.

It grows in littoral forest on rocky and sandy coasts, and is particularly common in sandy open habitats of atolls, often being the tree species closest to the ocean. On Midway and other Northwestern Hawaiian Islands, Tournefornia serves as nesting habitat for our shrub-nesting seabirds. On Midway, this plant flowers and seeds from May through November.

Since the tree is small, it is not very good for timber, but the wood is sometimes used for making gongs, canoe bailers, tool handles and carved handicrafts, and parts of the tree are reported to be used in native medicines in the Society Islands and Tokelau. The leaves were once used in the preparation of a red dye in Tahiti.

Ipomea pes-caprae

Indigenous. Trailing glabrous vine with purple stems, often rooting at the nodes, fleshy to nearly woody from a thickened taproot, up to 5 m or more long. Leaves simple alternate, blades fleshy, oblong to suborbicular, 3-10 cm long, notched at the tip, surfaces glabrous. Flowers solitary or in few-flowered cymes up to 15 cm long. Calyx or 5 unequal, ovate to elliptical sepals 8-13 mm long. Corolla funnel-form, pink to rose-purple, 3-5 cm long, shallowly 10 lobed. Fruit an ovoid to subglobose capsule 12-17 mm long, containing 4 dark, ovoid, densely hair seeds 6-10 mm long.

Pantropical in distribution, and is found on all the major high archipelagoes of Polynesia and all the low and high archipelagoes of Micronesia. It is one of the most abundant species on rocky and sandy beaches of high islands, sometimes forming almost pure stands, but is uncommon on atolls. On sandy beaches, its creeping stems extend almost down to the high tide mark.

In Hawaii, on Midway Atoll, Lisianski, Laysan, French Frigate Shoals, Nihoa and all the main islands. On Midway, flowers from May through November, fruits and seeds from August through December.

Pycreus polystachyos

Native to tropical and subtropical regions worldwide. In Hawaii, common on open or grassy, often disturbed areas, from mesic coastal sites to mesic and wet forest. Found on Midway Atoll and all of the main Hawaiian islands except Kaho'olawe. On Midway, this plant can be found in disturbed and wet areas. Plants are growing, and seeding from March through November.

Eragrostis paupera

Common name: Bunch grass

Indigenous. Perennial. Culms densely tufted, tough, stiff, strictly erect, up to 2 dm tall, sharply scabrous (rough-surfaced; bearing short stiff hairs), almost completely covered by leaf sheaths. Blades up to 5 cm long, but usually shorter, upper surface has short, stiff hairs or bristles. Inflorescences paniculate, weakly branched, sharply scabrous; spikelets few to ca. 40, straight to somewhat curved, 5-45 mm long, flattened, 1-2 mm wide. Caryopsis golden brown, somewhat flattened, subglobose to ovoid, 0.5-0.8 mm long, 0.4-0.5 mm wide.

Native to the Pacific equatorial region; in Hawaii occurring in coastal sites on coral sand, gravel ans saline flats, sometimes as a pioneer species. On Kure, Midway (Eastern and Spit islands), and Pearl and Hermes atolls, French Frigate Shoals, and formerly at Barber's Point, Oahu. On Midway, plants observed with inflorescences from May through November.

Native Plant Outplanting from January 1997 - August 2007