The Coastal Phyllostegia or Variable Phyllostegia was described in 1900, the species was originally discovered on the island of Laysan but was subsequently also found on the Kure- and Midway atolls in the northwestern Hawaiian Islands.
Hugo H. Schauinsland wrote the first notes about this species, that he discovered in 1896.:
“Phyllostegia variabilis Bitter nov. sp. Here and there on the E and W side near the beach. The numerous small flowers appear first during winter, beginning in November. It is a herbaceous plant, with few unbranched runners which I found to be 3/4 to 1 m long.” 
“… In 1896 it was scattered near the beach of the west and east sides (Schauinsland, 1899: 97). It was still present in small patches in 1903, mostly on the windward side (Christophersen and Caum, 1931: 11). it disappeared from Laysan before 1911.” 
The species is now completely extinct.
 Charles A. Ely; Roger B. Clapp: The natural history of Laysan Island, northwestern Hawaiian Islands. Atoll Research Bulletin 171. 1973  Hugo H. Schauinsland: Three months on a coral island (Laysan); translated by Miklos D. F. Udvardy. Atoll Research Bulletin 432. 1996
The Poko Cutworm, so named for its native name Poko, was one of the moth species, that in the time after the arrival of European settlers on the Hawai’i Islands were able to adapt quite well to the new set of circumstances.
The species reached a wingspan of about 4,9 cm.
The natural host plants of the caterpillars were several native species of Ihi (Portulaca spp.) as well as ‘Ilima (Sida fallax Walp.), but in the meantime they also adapted themselves to introduced plant species and fed on the leaves of thorn-apple plants (Datura spp.) and sugar cane (Saccharum officinarum L.). Furthermore they fed on several garden plants, especially of the legume family, e.g. beans, and therefore may not have been very welcome to gardens.
In 1899, Hugo H. Schauinsland wrote the following notes about his observations of this species on the island of Laysan.:
“Of the insects I found on Laysan, only the following … Spaelotis crinigera Butl.; the latter occurred in astonishingly hugh numbers. Its “grublike caterpillar” lives under ground on the roots of Eragrostis.” 
Even though the Poko Cutworm was distributed all over the Hawaiian main islands, it belongs to the extirpated species now, whereas the reasons for this seem still to be unknown up to date.
The species was last seen in 1926.
 E. C. Zimmerman: Insects of Hawaii 7, Macrolepidoptera. University of Hawaii Press, Honolulu 1958  Hugo H. Schauinsland: Three months on a coral island (Laysan); translated by Miklos D. F. Udvardy. Atoll Research Bulletin 432. 1996
The genus Pritchardia contains about 26 species, 22 of which occur only on the Hawaiian Islands, most of them being single-island endemics. Today, the northernmost population of these palms can be found on the little rocky island of Nihoa, where Pritchardia remota Becc. occurs, which apparently also occurs on the island of Ni’ihau.
There was once, however, another population of such palms even further north, on the island of Laysan, this population may indeed have been a endemic species, it disappeared sometimes during the late 19th century.
The first account that mentions this palm species dates from the year 1828, when the island Laysan was “discovered” by Europeans (which named it Moller).:
“Den 12. (24.) März betrat derselbe die neuentdeckte Insel Moller, eine ursprüngliche Korallenbank mit einem langen daran hängenden Riffe. Die Insel selbst scheint durch den Unrath der Vögel nach und nach etwas erhöht worden zu seyn, sie ist fast durchgängig bewachsen mit einer starken buschigen Grasart und zum Theil mit kurzem Gesträuche, zwischen welchem einige zwergenhafte Exemplare einer Art Fächerplame aufgekommen waren.“
“The 12th (24th) March the same [C. Isenbeck, ship’s doctor on board the “Moller”] entered the newly discovered island Moller, a pristine coral bank with a long attached reef. The island itself seems to have been somewhat elevated by the filth of the birds, it is nearly continuously overgrown with a strong shrubby grass species and partly with short shrubs, between which some dwarfish specimens of a species of fan palm had come up. ” 
At around 1890, the Hawaiian kingdom granted permission to British guano miners to exploit the large seabird colonies of the island – not only fro guana, but also for eggs and “feathers”, which actually meant that whole birds respectively their wings were exported from Laysan.
Probably shortly after the palms had disappeared, apparently most had been destroyed for their wood. The sad remains were still found in 1896, as Hugo H. Schauinsland, a German zoologist, tells us.:
“Not too long ago, palms have also lived on the island, and, as the many remnants of their rotten stumps show, they were very numerous. However, the last living examples died off a few years ago, and since we cannot find a spot anywhere on the island to escape the burning rays of the sun, we miss their shade-providing crowns. It is not unlikely that castaways contributed to their demise, for at times, they were for sure present on the island. I found heaps of coal, in a few places, still showing the characteristic structure of palm wood. These could have been remnants of campfires, or else signs of fires kindled by carelessness. A final noteworthy observation about the flora of laysan is the complete lack of ferns, mosses and lichens.” 
Hugo H. Schauinsland also wrote the following lines.:
“Finally, we should remember the palms …, which Kittlitz already mentions (in 1834, in the Museum Senckenbergianum). In 1859, there were still 5 specimens on the island (according to capt. Brooks), the tallest reaching 15 ft. I myself saw no more living specimens, although i found numerous stumps and pieces of root in the northern part of the island; some having a diameter of 50 cm. I also found numerous remnants in the southern part of the island, not far from the lagoon. Thus, the original numbers of trees were certainly several hundred. According to verbal information, the palms had hugh fan-shaped leaves and long florescences and fruit racemes. in all likelyhood it was Pritchardia.” 
The photo below shows two of these dwarfish palms once found on Laysan, the date and the photographer of this photo, however, are not known (at least not to me).
 Heinrich von Kittlitz: Nachricht von den Brüteplätzen einiger tropischer Seevögel im stillen Ozean In: Museum Senckenbergianum: Abhandlungen aus dem Gebiete der beschreibenden Naturgeschichte 1: 116-126. 1833  Hugo H. Schauinsland: Three months on a coral island (Laysan); translated by Miklos D. F. Udvardy. Atoll Research Bulletin 432. 1996
The Atoll Achyranthes was described in 1979 as a part of a genus monograph, it is known from several specimens, the oldest of which dates from 1896, which were formerly thought to represent another taxon, the Round-leaved Shining Chaff Flower (Achyranthes splendens var. reflexa Hillebr.) [currently Achyranthes splendens var. rotundata Hillebr.].
The species is thought to have been endemic to the northwestern part of the Hawaiian island chain, it is known from at least four of the atolls/islands: from Kure, Laysan, from Midway as well as from the Pearl and Hermes Reef.
“There are no collection of this species from the southeastern islands of the chain, even on those with an atoll ring surrounding a volcanic core. This species is a part of the native flora of four of the northwestern atolls of the Hawaiian leeward group. It still occurs on Kure, and on Pearl and Hermes. On Midway it was collected in 1902; on Laysan in 1903, and it is doubtless extinct on these two islands.” 
The species, if it is one, was a 1 to 2 m tall shrub with all parts covered with very fine hairs. The elliptic to obovate leaves were 2 to 5,2 cm long and 1,2 to 3,8 wide, the base were cuneate, the apex obtuse or subacute. 
The island of Laysan has lost all of its vegetation due to the stupid intentional introduction of Guinea Pigs (Cavia porcellus (L.)) and Rabbits (Oryctolagus cuniculus (L.)) at the beginning of the 20th century, which simply consumed all of the plant material in existence. On the other atolls and islands named above the species disappeared apparently due to human activities, for example the building of military bases.
It was last collected on the Kure Atoll in 1964 and in 1969 on the Pearl and Hermes Atoll. 
A last remark: the author of this species has actually named a lot of species, many, I mean perhaps most of them are now no longer accepted as being valid, this may well also apply to the Atoll Achyranthes, which after all may indeed someday turn out to be nothing but a Round-leaved Shining Chaff Flower (Achyranthes splendens var. rotundata Hillebr.).
 Harold St. John: Monograph of the Hawaiian species of Achyranthes (Amaranthaceae). Hawaiian plant studies 56. Pacific Science 33(4): 333-350. 1979
The Laysan Owlet Moth was described in 1913, it was endemic to the island of Laysan in the northwestern part of the Hawaiian island chain, but may also have occurred on the Pearl & Hermes Reef.
The quite variable species reached a wingspan of about 2,2 to 2,5 cm.
The caterpillars of this species were found feeding on the leaves of ‘aki ‘aki (Sporobolus virginicus (L.) Kunth). 
 Otto H. Swezey: Two new species of moths from Laysan Island. Proceedings of the Hawaiian Entomological Society 3: 18-19. 1913  E. C. Zimmerman: Insects of Hawaii 7, Macrolepidoptera. University of Hawaii Press, Honolulu 1958
The Laysan Leaf-roller was described in 1913 (or 1914, according to other sources), the species is known only from the island of Laysan, Hawaiian Islands and is the sole known member of its genus known from the northwestern Hawaiian Islands.
The species reached a wingspan of 1,9 to 2,2 cm, the forewings were mainly light fuscous with a darker costa and median band, the hindwings were light fuscous, somewhat suffused with a whitish wash.
The biology of this species is not known, its larvae, however, are thought to have fed on some native grass species. 
 Otto H. Swezey: Two new species of moths from Laysan Island. Proceedings of the Hawaiian Entomological Society 3: 18-19. 1913  Elwood C. Zimmerman: Insects of Hawaii 8; Lepidoptera: Pyralidae. University of Hawaii Press, Honolulu 1958