Question: Which species is more rare, the Cussonia or Strombocactus?

Context paragraphs:
Seemannaralia gerrardii: Seemannaralia gerrardii, commonly known as the wild-maple or mock carrot tree, is a species of flowering plant of family Araliaceae.  It is the sole member of genus Seemannaralia, and is endemic to South Africa, where it occurs in the Eastern Cape, KwaZulu-Natal, Limpopo and Mpumalanga provinces.  It was originally included in genus "Cussonia".  "Seemann-" and "gerrardii" commemorate Berthold Seemann and William Gerrard respectively, while -"aralia" suggests the family or its type genus, "Aralia".

Cussonia sphaerocephala: "Cussonia sphaerocephala" is a species of tree in the Araliaceae family.  It is known as the Natal Forest Cabbage Tree; in Afrikaans it is called the Natalse Boskiepersol, and in isiZulu as Umsenge.

List of birds of Costa Rica: Although Costa Rica is a small country, it is in the bird-rich neotropical region and has a huge number of species for its area.  The official bird list published by the Costa Rican Rare Birds and Records Committee of the Asociación Ornitológica de Costa Rica (AOCR) contains 918 species.  This number is more than have been recorded in all of the United States and Canada combined.  Of those species, seven are endemic (three of which are found only on Cocos Island), 63 are rare or accidental, and four have been introduced by humans.  Another 73 are near-endemic with ranges that include only Costa Rica and Panama.  Twenty-three species, including five of the seven endemics, are globally vulnerable or endangered.  Over an area of 51,100 km, an area smaller than West Virginia, this is the greatest density of bird species of any continental American country.  About 600 species are resident, with most of the other regular visitors being winter migrants from North America.

List of birds of North Carolina: This list of birds of North Carolina includes species documented in the U.S. state of North Carolina and accepted by the North Carolina Bird Records Committee (NCBRC) of the Carolina Bird Club.  As of January 2016, there are 464 species and a species pair definitively included in the official list.  Twelve additional species, one of which is identified only at the genus level, are on the list but classed as provisional.  Of the 476 species, 84 are rare anywhere in the state, 81 are rare in some part of the state or in a single season, six have been introduced to North America, and four are extinct.

List of birds of South Carolina: This list of birds of South Carolina includes species documented in the U.S. state of South Carolina and accepted by the South Carolina Bird Records Committee (SCBRC) of the Carolina Bird Club.  As of July 2016, there are 419 species definitively included in the official list.  Thirteen additional species are on the list but classed as Provisional I (see definitions below).  Of the 432 species on the list, 106 are rare anywhere in the state, 36 are rare away from the coast, four have been introduced to North America, and four are extinct.  Fifteen species are classed as Provisional II and 11 as Hypothetical as defined below.

Strombocactus: Strombocactus disciformis is a rare species of cacti and the only species of the genus Strombocactus.  The plant originates from Central and Northeast Mexico.

Gara-Gel State Reserve: Gara-Gel State Reserve or Qaragol State Reserve was established on the area of 240 hectares in 1987 for protection and preservation of rare ecological system of the lake of glacial origin and natural complexes surrounding the water basin.  The lake feeds mainly from rains and spring water.  Lake Ishigli-Gara-Gel is situated at a height of 2, 658 m above sea level in the southern part of the Karabakh volcanic plateau near the foothills of several mountains with a height of 3, 200-3, 500 m. the lake is a relict water reservoir, which was formed in the crater of an extinct volcano.  The length of the lake is 1,950 m, its maximum width is 1, 250 m, length of its coastline is 5, 500 m, maximum depth – 7.8 m, volume of water – 10 million m3, area of the lake 13 km2.  Water flow is mainly due to melted snow and rainwater, partially spring water.  In terms of botany and geography the Karabakh Plateau is situated between the Caucasian and Armenian-Iran provinces, which determines the specifics of the local flora.  The flora of the reserve includes 102 species and subspecies of vascular plants from 68 general and 27 families.  The lack of flora is explained by the fact that the reserve covers only the lake, and many rare and endemic species grow beyond the reserve area, but close to its borders.  The vegetation of the coastal area of the lake is represented mainly by meadows with the dominance of Trifolium and Tragacantha and Astragalus.  The swamp flora and vegetation are limited because of the height of the area.  There are only two species of plants in the lake: Polygonum amphibium and Ranunclus.  In 1967, a type of Sevan trout, included in the Red Book, was introduced into the lake.  The reserve is an inter-republic reserve.  The reserve is under occupation.  Adjacent to the borders of the reserve there are areas with rare and endangered species of plants such as Euphrasia, Potentilla and others.

Rare Species Conservation Centre: The Rare Species Conservation Centre (RSCC) was a conservation centre and zoological gardens situated just outside Sandwich in Kent, England, operated by The Rare Species Conservation Trust, a UK registered charity.  Its purpose was to educate visitors and create awareness of the plight of some of the world’s lesser-known rare and endangered species of animal.  It was home to rare and unusual animals.  It closed due to lack of funds on 31 August 2015.

List of birds of Newfoundland and Labrador: This is a list of bird species confirmed in the Canadian province of Newfoundland and Labrador.  The Bird Records Committee of Nature Newfoundland & Labrador (Nature NL) lists 398 species as occurring in Newfoundland as of March 2016.  Through eBird, seven additional species have been recorded in Labrador, and two more have been recorded in Newfoundland since the Nature NL checklist was published.  Of these 407 species, 112 are rare and 79 are very rare as defined below.  Two were introduced to North America.  One species is possibly extinct.  Another species formerly found in Labrador is known to be extinct but is not on the Nature NL checklist.

Cussonia: Cussonia is a genus of plants of family Araliaceae, which is native to the Afrotropics.  It originated in Africa and has its center of distribution in South Africa and the Mascarene Islands.  Due to their striking habit, they are a conspicuous and easily recognizable group of plants.  Their genus name commemorates the botanist Pierre Cusson.  The Afro-Malagasy and Asian "Schefflera", and Afrotropical "Seemannaralia" genera are related taxa that share several of its morphological characteristics, among which the leaves borne on the end of branches, inflorescences carried on terminal branches or stems, and reduced leaf complexity in developing inflorescences.

Supporting paragraphs: Cussonia Strombocactus
Answer: Strombocactus