Achyranthes atollensis H. St. John

Atoll Achyranthes (Achyranthes atollensis)  

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.” [1]  

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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. [1]  

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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. [1]  

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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.).  

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References:  

[1] Harold St. John: Monograph of the Hawaiian species of Achyranthes (Amaranthaceae). Hawaiian plant studies 56. Pacific Science 33(4): 333-350. 1979  

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Photo: David Eickhoff 
http://nativeplants.hawaii.edu

(under creative commons license (2.0)) 
http://creativecommons.org/licenses/by-nc-sa/2.0 

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edited: 23.11.2018