Question: Which species appears in areas more westernly, Cleistocactus or Rhynchostylis?

Context paragraphs:
Cleistocactus hyalacanthus: Cleistocactus hyalacanthus is a species of columnar cacti in the genus "Cleistocactus".  The name comes from the Greek "kleistos" meaning closed because the flowers hardly open.

Acartia teclae: Acartia teclae is a species of copepod belonging to the family Acartiidae.  This species was discovered when specimens previously identified as "Acartia clausi" were examined and found to belong to a separate species.  This species appears to have a similar range (Mediterranean Sea and north eastern Atlantic Ocean as far north as Great Britain) to, and occupies similar brackish estuarine habitats as, "Acartia lefevreae" but differs in the absence of spines on the dorsal part of the posterior body segment (metasome).

Open Bay Islands skink: The Open Bay Islands skink (or Open Bay Island skink), "Oligosoma taumakae", is a species of skink.  It was described from the Open Bay Islands, off the west coast of the South Island of New Zealand.  This species is diagnosed on the basis of several morphological characteristics, and its specific status is supported by mitochondrial sequence data (ND2, ND4).  The new species appears to be most closely related to "Oligosoma acrinasum", "Oligosoma infrapunctatum", "Oligosoma otagense" and "Oligosoma waimatense".  Predation by a flightless rail, the weka, which is native to New Zealand, but was introduced to the Open Bay Islands, is a major conservation concern.  Until recently known only from the Open Bay Islands (both Taumaka and Popotai Islands), the species has subsequently been discovered on two apparently predator-free vegetated rock stacks located off the coast of Barn Bay, 52 km southwest of the Open Bay Islands.

Cosmos parviflorus: Cosmos parviflorus is a North American species of plants in the sunflower family.  Common names include southwestern cosmos in the US and juve or aceitilla blanca in Mexico.  In many places it is a common weed in agricultural fields, although it also grows in grassy meadows in forested areas.  The species appears to be native in Texas, New Mexico, Colorado, Arizona, and Utah.  Collections have also been made from Massachusetts, Maine, Maryland, Missouri, Rhode Island, although it appears to be introduced to those regions.  It is widespread in Mexico from Chihuahua to Oaxaca.

Rhynchostylis: Rhynchostylis (abbreviated Rhy in the horticultural trade) is a genus in the orchid family (Orchidaceae), closely allied to the genus "Vanda" (from which it differs in the one-lobed lip of the flower) and comprising four currently accepted species native to the Indian Subcontinent, China, Indochina, Malaysia, Indonesia and the Philippines.  The name consists of a compound of two Greek elements : "rhynchos" 'beak' and "stylis" 'column' - in reference to the very boad, fleshy column of the flower.

Cleistocactus tominensis: Cleistocactus tominensis is a species of columnar cactus in the genus "Cleistocactus", endemic to Bolivia, where it is found in forests, on cliffs, and in inter-Andean valleys at altitudes of 900 to 2,200 meters.

Quantula striata: Quantula striata, also known as "Dyakia striata", is a species of medium-sized, air-breathing, tropical land snail.  It is a terrestrial, pulmonate, gastropod mollusk in the family Dyakiidae.  This species appears to be unique among terrestrial gastropods in that it is bioluminescent: Its eggs glow in the dark, and juveniles and most adults give off flashes of green light.  It is the only species in the genus Quantula.

Cleistocactus: Cleistocactus is a genus of columnar cacti native to mountainous areas - to 3000 m - of Peru, Uruguay, Bolivia and Argentina.  The name comes from the Greek "kleistos" meaning closed because the flowers hardly open.

Cleistocactus morawetzianus: Cleistocactus morawetzianus is a species of columnar cactus in the genus "Cleistocactus", endemic to Peru.

Hopliancistrus tricornis: Hopliancistrus tricornis is the only species of the genus Hopliancistrus of suckermouth armored catfish.  This species reaches a length of 10.4 cm SL.  It is endemic to Brazil and can be found in the Tapajós and Xingu River basins.  This species appears similar to members "Lasiancistrus", however it lacks the synapomorphies and has five rows of plates on the caudal peduncle instead of three like those found in "Lasiancistrus".  It is characterized by three stout, strongly curved odontodes on either side of the head in males.

Supporting paragraphs: Cleistocactus Rhynchostylis
Answer: Cleistocactus