As Jason rightly guessed, this is a Schlumbergera species, specifically S. truncata, also known as the Thanksgiving cactus (which has toothed edges as shown). It’s related to the Christmas cactus (S. bridgesii – scalloped edges) and the Easter cactus (S. gaertneri, whose segments are three-sided rather than flattened). [Disclaimer: the nomenclature of this genus and its species is a mess. Even the university websites disagree on whether it’s Schlumbergera, Hatiora, or Rhipsalidopsis. Now you know why I am not a taxonomist.]
On to the more interesting question – those hairs. The green segments you see on these plants are not leaves, but flattened stems, called phylloclades (or cladodes). Phylloclade comes from the Latin word for leaf (phyllo-) and the Greek word for branch (-clade). These leaf-like branches are the primary photosynthetic organs for the plant.
So where, you may ask, are the leaves? That’s what those hairs are! And if you look at your Christmas/Easter/Thanksgiving cactus when it begins to set buds, you’ll see that the buds arise from the leaf axils – that point where the leaf joins the stem. This distinction is why these hairs are, morphologically, the true leaves of the plant.
Very cool. I have a Christmas Cactus that has been in the family for many decades (I’m the 3rd generation at least…) and it is different from many Christmas cactus that I see around…any good resources for help with identifying mine? It’s main difference from what I see currently is that it’s phylloclades (how often do newly learned words get to be put to use right away…) are smaller than what I’ve seen on most other Christmas Cactus. The flowers are also smaller. It is a well loved family item, and sometimes cuttings are given as gifts to younger family members.
Matthew, there seem to be many hybrids within this genus. You might check out this reference: McMillan, A. J. S. & J. F. Horobin. 1995. Christmas cactus: The genus Schlumbergera and its hybrids. (Just an aside: my pictured Thanksgiving cactus was my grandmother’s. I also take cuttings and give them away as gifts. I think I might do that for our upcoming family reunion – thanks for the idea!)
Taken from the introduction of my MS thesis (Rohwer, 2002, so it might be obselete now according to those darn taxonomists):
“Most recently and more accurately, Easter cacti have been properly labeled as species of Hatiora by botanical, scientific, and educational literature (Barthlott and Taylor, 1995; Dole and Wilkins, 1999; Karle and Boyle, 1999). Rhipsalidopsis is the subgenus including Hatora. Therefore, referring to Easter cactus as Rhipsalidopsis may be correct, but this nomenclature includes H. epiphylloides, a nearly extinct relative. The two other species in the Rhipsalidopsis subgenus are H. gartneri and H. rosea.”
“Hybrids of H. gaertneri and H. rosea are labeled H. x graeseri. H. gaertneri and, more commonly, H. x graeseri, are the typical Easter cacti cultivated today (Barthlott, 1979; Boyle, 1990; Boyle, personal communication).”
I’m not sure, but those hairs may be glochids.
It figures…there had to be an expert out there that reads the blog! Charlie, I will bow to your interpretation of the taxonomy. The hairs might
very well be glochids, but my understanding is that they are still, morphologically speaking, modified leaves.
On Taxonomy. While putting together a workshop on basic insect id for Master Gardeners manning the hot line, I came across this quote about true bugs that sums up my reaction to the subject:
A possibly paraphyletic group of insects known as the Homoptera is sometimes included within the Hemiptera, even though they lack the toughened areas on the first pair of wings. Some entomologists group both Hemiptera and Homoptera within the group Heteroptera; others use the name Heteroptera for what we have called the Hemiptera and use Hemiptera for the Heteroptera. Confused? So are we.
If it’s confusing for you PHd types, imagine the reaction of us laymen. 😉
A possibly paraphyletic group of insects known as the Homoptera is sometimes included within the Hemiptera, even though they lack the toughened areas on the first pair of wings. Some entomologists group both Hemiptera and Homoptera within the group Heteroptera; others use the name Heteroptera for what we have called the Hemiptera and use Hemiptera for the Heteroptera. Confused? So are we.
Ray, our Sustainable Landscapes and Gardens book has an excellent chapter on entomology. Art Antonelli, our recently retired extension entomologist extraordinaire, has both a practical taxonomic key and color photographs depicting both the Hemiptera and Homoptera.
I have always wondered why my “Easter cactus” bloomed in the fall. I guess I can accept the fact that I have a Thanksgiving cactus and stop getting angry at it for blooming during the wrong holiday!
The Sustainable Landscapes and Gardens books are great by the way!
I have always wondered why my “Easter cactus” bloomed in the fall. I guess I can accept the fact that I have a Thanksgiving cactus and stop getting angry at it for blooming during the wrong holiday!
The Sustainable Landscapes and Gardens books are great by the way!