Identification of a day blooming climbing cactus

[goliad]

I collected this cactus in 1998 from a yard in Three Rivers, Texas. Here is the day bloom: .
And here is the cactus growing on a huisache: .
The flower lasts a single day. The stems are square in cross-section. Can anyone help?

[7george]

Some kind of Selenicereus.

[DaveW]

Bit of a puzzle here. Most night flowering plants are usually white flowered, therefore a pink bloom is not common. The nearest match I can get is Selenicereus wrecklei. That is said to have white flowers with a red centre, but some illustrate it with pink flowers:-

http://www.flickriver.com/photos/tags/s ... teresting/" onclick="window.open(this.href);return false;

https://www.flickr.com/photos/68114448@ ... 185052237/" onclick="window.open(this.href);return false;

Original description:-

http://www.cactusexpert.org/cactus-fami ... weber.html" onclick="window.open(this.href);return false;

In theory any plant with red in the flower can sometimes produce a totally pink or red flowered sport, or even reddish flowered race (there is a population of red flowered Notocactus submammulosus in habitat). The other explanation of course is hybridity, but it would be interesting to know if the pink flower was found in habitat or arose in cultivation?

http://www.mobot.org/MOBOT/research/Edg ... pick.shtml" onclick="window.open(this.href);return false;

Click on pictures to enlarge:-

http://midwestherbaria.org/portal/taxa/ ... 20wercklei" onclick="window.open(this.href);return false;

[oldcat61]

Could be a Harrisia. Friends in Florida have one growing in a tree that is not that pink. Mostly white with pink outer petals. The flowers open in the middle of the night but last all day, so George may think it's a day bloomer. I thought about bringing cuttings back but just too big & rangy for a GH. Sue

[7george]

My 1st thouight was about S. inermis(syn. S. wercklei) too, but S. spinulosus also looks similar and originating from Mexico is more likely to grow in Texas.

S. spinulosus (DC) B+R 1909/CUSNH 12: 431. B: 08457
Cereus spinulosus DC 1828/MMHN 17: 117.
Distr: MX (Hidalgo, Nuevo Leon, Oaxaca, Puebla, Quere-
taro, San Luis Potosi, Tamaulipas, Veracruz); 55 - 2100 m.
Br: 1 - 2 cm 0 ; ri: 4-5; ar: 1.5 - 2.5 cm apart; sp: 6 - 8, only 1 mm;
fl: 10 - 12.5 x 7 - 8.5 cm; pear spiny but without silky hairs; otep pale
brown-green; itep white to pale pink

Descr. from NCL.

[DaveW]

You may be right George, the pink flower rather throws one off track since most Selenicereus species are described with white nocturnal flowers (opening at night, though they often persist into the next day). Did find this one for S. spinulosus though:-

http://cactus-epiphytes.eu/esp_photo_1281_1h_p14.htm" onclick="window.open(this.href);return false;

This was one of the early illustrations of S. spinulosus though:-

https://commons.wikimedia.org/wiki/File ... Cereus.png" onclick="window.open(this.href);return false;

https://www.flickr.com/photos/22048801@N03/4679945600" onclick="window.open(this.href);return false;

Unfortunately colour variation of flowers in habitat is not well recorded and the original description is often only based on a single plant. You can always email a digital picture to a botanical garden and ask if they can identify it. You can usually find their email addresses on the Web.

[goliad]

If it helps, I'm posting a photo of a fruit and a close up of a stem.
The fruit is the only one I've ever gotten despite many blooms. I have many of these climbing trees, but all are a single clone from the original collection. Perhaps self sterile?
The stems come in three types. The most common is four sided (pictured) but also five and six sided. The stems only branch 1) when injured, and then only below the injury, and 2) when the stem droops away from the surface it's growing on, and then only at the top of the droop.
So far, I'm leaning toward Selenicereus spinulosus based on the posted photos.

[7george]

Should be Selenicereus spinulosus. It is considered a native plant for Texas.

http://www.efloras.org/florataxon.aspx? ... _id=130014" onclick="window.open(this.href);return false;

[tumamoc]

Whatever it is, I'm jealous that you can grow yours outdoors like that.