Princess of the Night, Snake Cactus (Selenicereus pteranthus)

Princess of the Night, Snake Cactus
Selenicereus pteranthus

Growing outdoors in Santa Barbara, California

Lovely green stems, but to me this looks more like some sort of a Stapeliad. I don't see any spines on it, really. Did it ever bear these big white flowers the cactus is renowned for?
I tend to think it is a different plant.

Well that's what the garden has it labeled as. Never been to the garden at night so never seen the flowers. It is definitely a cactus has many little tiny spines at every raised nipple on the plant- covers the side of a wall like some sort of climbing cactus, too. Not sure if this cactus flowers all year long (maybe April is not flowering season), but morphologically it is identical to Selenicereus grandiflorus that I have seen in other photos- even down the the subtle striping. But if there is mistake of identification, I apologize. I will try to find out more about this plant next time I'm at the gardens.

Irene, the pictures you posted look just like Bob's.
http://plantsdatabase.com/showpicture/35519/
The other 'Queen of the Night' is Epiphyllum oxypetalum.

I think that taxonomists are now trying to combine many of these Selenicereus into forms or varieties of Selenicereus grandiflorus. For instance, I acquired mine as Selenicereus urbanianus but in many places I now see it listed as Selenicereus grandiflorus v. urbanianus. To make matters worse, my particular plant is the monstrose form, so it would be called Selenicereus grandiflorus v. urbanianus f. monstrosus. How's that for a name.

Like I said, some of the other Selenicereus such as S. pteranthus and S. macdonaldiae are being combined under S. grandiflorus as merely varieties or forms, so it can be quite confusing.

-Ron-

Yes it is confusing, but this plants is quite easy to recognize. It is Selenicereus macdonaldiae. The green knobby stems are typical. It has one of the largest flowers of all Selenicereus and quite distinct is its relatively loose shape, short stamens and very long style. But they are all closely related:

S. macdonaldiae: [HYPERLINK@toptropicals.com]



The most commonly grown "species" i a strict sense is:

Species with lost of hair on the floral tube.

S. grandiflorus - very unknommon and almost never cultivated. Thin stems with 5-8 ribs Here is a good image: [HYPERLINK@www.cybertruffle.org.uk]

S. pteranthus - by far the most common species in cultivation. Rather thick stems with 4-5 ribs and short, often blackish spines. Most images on internet is this species. Image: [HYPERLINK@www.botanik.uni-karlsruhe.de]

S. boeckmannii - is very similar to S. pteranthus but said to have brown areoles. [HYPERLINK@www.dipbot.unict.it]

S. urbanianus (West Indies) and S. coniflorus (Mexico) are long spined versions of S. pteranthus and hard to separate.

S. urbanianus: [HYPERLINK@www.kingsnake.com]

S. coniflorus: [HYPERLINK@www.kammlott.net]

S. validus - form rather small pendent plants that flowers from the base. [HYPERLINK@www.koehres-kaktus.de]

S. hamatus - easily reconized by the hooked stems: [HYPERLINK@www.rufer-blumen.ch]

Two rather commons species without hairy tubes are:

S. vagans - has large flowers and often very pointed tepals: [HYPERLINK@www.dkimages.com]

S. spinulosus - smaller flowers, shorter spines and fewer rins than S. vagans: [HYPERLINK@gardenbreizh.org]


Note that most of these images are posted on internet as S. grandiflorus.

Sorry, I don't know how to publish links here....