It's not Christmas, but here's a Cactus!

Species name: Schlumbergera truncata

Common name: Christmas cactus

Location: UWO Greenhouse

I was pondering saving this blog for sometime around Christmas next year, but when I saw how the last picture turned out I wanted to brag about it right away. Doesn't it look like it's illuminated from the inside?! One of my proudest moments, and I have no idea how to re-create it. :)

This species of Christmas cactus (there is more than one, and most of the Christmas cacti sold in store around Christmas are actually hybrids) is native to a very small area in Brazil, in the Amazon jungle near Rio de Janeiro. It was once severely over-harvested in the wild due to the ornamental plant trade, and so European species of the same genus were purposely introduced into the wild to prevent over-harvesting of the native species. Since then, quite a bit of hybridization has occurred between the two species (both in the wild and in greenhouses), and so most that are sold in stores are not a "true" species. The Christmas cactus is an epiphyte, living on standing tree trunks or off of tree branches. It also has the ability to grow on the surface of rocks in very humid areas, this is called an epilythic plant. There are a few plants I've already blogged about that are also notorious lithophytes: the monkey pitcher plant (read about it HERE), paph orchids (read about them HERE), staghorn ferns (read about them HERE or HERE), and other more "regular" species of ferns (read about one HERE). There are also very close relatives of the pineapple that grow on rock faces in the tropics, and can even grow (and commonly do) on telephone and electrical wires!

There are very few pests of Christmas cactuses, but they can suffer from all of the same diseases and pests that any greenhouse plant can (aphids, mealybugs, and Fusarium vascular wilt; all very common in greenhouses). It does have a unique disease: Christmas Cactus X virus. Like with the Hosta X virus, there is no known solution to infection once it is visible in the plant, and so it is strongly suggested that plants be destroyed once symptoms are noticed (usually a yellowing around the vascular system of the plant, the "veins", and the infection can jump from section to section in the stem).

Swim little fishies!

Species name: Nemanthus wettsteinii

Common name: goldfish plant

Location: UWO Greenhouse

This is one of the few tropical species of plants that grow well indoors that I'm disappointed no one has told me about before a couple of weeks ago. To me, these flowers are just plain awesome. Not just awesome for the fact that they literally look like goldfish (unlike other plants named after animals like the Shrimp Plant; sorry shrimp plant!), but because of their unique adaptations to target their preferred pollinators. The goldfish plant is native to the Amazon and surrounding areas, with the native range stretching from Brazil up to Mexico. This plant, while a very popular indoor plant in the southern United States, is still very common in the wild. It also grows incredibly easily indoors, so the need to return to the wild to collect more plants is rare.

The reproduction of this plant is fascinating. In fact, it hardly ever happens, and never happens sexually in this species. Hard to believe? I agree! But the biology has been well documented, and so here's what happens. The flowers are just an offering to species that need nectar in the wild, which is practically unheard of in the wild. This species of Nemanthus is asexual, meaning the flowers are not produced for the purpose of reproduction. Close relatives of the goldfish plant, who have redder flowers that are less shaped like goldfish and more like tubes, do reproduce via seeds (which requires sexual reproduction) so it appears as if this plant has lost the ability somewhere down the line. Instead, it reproduces asexually by severing its young branches, having them fall off the plant, ideally roll down a hill and root in a new location. In the wild these plants are often epiphytes, meaning they'll grow on just about any surface that they can grab onto (and rarely obtain nutrients from this surface; they get those from the humid air). The goldfish are just swollen sacs of nectar available for any insect or bird to exploit at their will. Hummingbirds, despite the flowers of this species being orange and not red, are still attracted to the flowers and will use it as a preferred nectar source when the flowers are in full bloom. Some insects with biting mouthparts will chew tiny holes in the bottom of the goldfish stomach to allow the nectar to freely flow out of the flower, and drink all they can get before returning to their nest. Other birds will use this same strategy, poking holes in the flowers and drinking the nectar that flows out. Every so often the goldfish plant will make something that looks like seeds when the flowers are spent, but they are sterile and not worth collecting since they will not produce a new individual (bananas are like this also; we call this not being "true to seed").

Like many succulent plants with fleshy leaves, the goldfish plant produces chemicals in the leaves that are mildly irritating to the skin. If you have sensitive skin and are planning on propagating this plant by snapping off leaves and putting them in water to root (it really is that easy to make a new plant!), make sure you wear gloves and you'll be fine. Cats and dogs (and other indoor pets) usually stay away from this plant despite having flowers that look like they would be fun to play with. There must be some kind of scent emitted from the leaves or flowers that lets them know it shouldn't be messed with. Goldfish plants are quite drought tolerant, so ignoring them won't bother them too much. They are also frost-tolerant (reportedly surviving brief exposures of -5 degrees Celsius or about 23-25 degrees Fahrenheit) so forgetting them outside on a cold night isn't a big deal.

A word of warning, however, if you like using these plants as ornamental garden plants in baskets during the summer and have a backyard garden: they carry viroids. A viroid is like a virus, being able to be transmitted from plant to plant when they come in contact (or when the sap of one plant is on the leaf surface of another, where it can enter the leaf breathing pores or stomata). Viroids are present in many plants, and it is believed that some are just the result of a virus that had infected the plant but had mutated to no longer be able to reproduce so gets stuck in the plant as a sort of virus fossil or relic. Some viroids, however, are still able to cause disease in plants, especially crop species. The viroid that the goldfish plant carries causes no symptoms in the plant so you would never even know it had it...until it comes in contact with either potatoes or tomatoes. Then it wreaks havoc. The symptoms in potatoes and tomatoes are quite severe, reducing the yield of crops of these two plants quite drastically. Best to keep these plants away from each other! Viroids cannot be spread through the air, and this particular viroid doesn't last very long outside of the plant, so having them in the same garden is no problem as long as there's a distance between them.

Another epiphytic fern

Species name: Platycerium bifurcatum

Common name: elkhorn fern, staghorn fern

Location: UWO Greenhouse

This species of staghorn fern is native to Australia and the surrounding areas, in tropical rain forests (you can read all about another species of staghorn fern HERE). Staghorn ferns are not parasites despite commonly growing off of other trees; they merely use these trees for support, and gather most of the nutrients they need to survive from the air. They will also commonly grow on dead standing trunks, and are important in helping break down organic material to return it to the soil, a vital process in any ecosystem (but a process that must be exceptionally fast in tropical systems because they are so productive) called nutrient cycling.

All ferns can reproduce in two ways, but most of the time you only notice one of these ways. Ferns are vascular plants, but they are in a group that branched off before the "invention" (the evolution) of seeds. So, like mosses and lycophytes, they reproduce via spore production. This spore production occurs on fertile fronds of ferns (what we call "leaves") in sori (sing. sorus), or the brown powdery masses on the underside of the leaves. Sometimes they're in distinct clusters, and in other species they completely cover the outside bottom surface of the frond. Where the sori and located and what they look like can be an important factor in distinguishing species! When spores germinate, they don't produce more fronds. They produce tiny little plants called "gametophytes" (the frond is the "sporophyte", a plant [-phyte] which produces spores [sporo-]) which produce gametes just like regular plants do. The gametophytes produce eggs and sperm (in higher plants, "plant sperm" is pollen), which fuse together to form the zygote which matures into the sporophyte. Normally, none of us are observant enough to notice the gametophyte, because it is so incredibly small (rarely more than a few millimetres across) but in the staghorn fern they can be up to 3 cm across. I didn't notice any while I was taking photographs, but I also wasn't looking very hard.

The staghorn fern, like many species of fern, produces two different types of fronds. The first type, the sterile fronds, are large and shield-shaped. Their role is to protect the roots of the fern from drying out, and in some species act as reservoirs to catch rainwater. The other type of frond is the fertile frond, which are the long, antler-shaped leaves coming out of the opening in the basal fronds. When one basal frond starts to rot (something which I imagine must happen quite frequently; if they're designed to catch water and protect something that must always be wet, they probably rot away quite quickly!), it is replaced by a new basal frond growing off the roots which you can see in the bottom photo. The production of this new basal frond is incredibly rapid; it can go from being a few millimetres across to a few centimetres across in a week or less.

An epiphytic fern

Species name: Platycerium superbum

Common name: staghorn fern

Location: Dominican Republic

This species of fern is a very popular garden plant for tropical gardens, and indoor gardeners with green thumbs are also causing this plant to rise in popularity in greenhouses. This species of staghorn fern is native to a small area in Australia, but is now propagated and easily grown (without being invasive) worldwide in tropical areas. There are about 15 other species in the genus ranging in origins from South America to Asia and everywhere in between. North America and Europe are the only two continents (assuming Antarctica is a given to be inhospitable to tropical plants) that could potentially have staghorn fern habitat that have no native species.

Anyone who's been to Puerto Plata ("Silver Port" in Spanish; named after the trees that are so common there that have bright green leaves on the top but when they flutter in the wind they flip over to reveal their shiny silver underside) has either seen or has taken a ride on the cable car that goes up the mountain. At the top is a giant Jesus statue (very similar if not identical to the one in Rio; it was actually a gift from Brazil) on a dome that used to be a jail but is now a gift shop, and a protected nature preserve. The people in charge of the nature preserve are trying their best at not only educating the public about native Dominican plants, but also conserving habitat suitable for plants that are incredibly rare worldwide. This species of staghorn fern, while not currently at risk for extinction, is becoming more and more rare due to wild harvesting for the gardening industry. The other danger to any Platycerium species is that they are a type of plant called an epiphyte. This is a plant that cannot live on the ground, and instead needs to live on the side of another plant. This doesn't mean that the epiphyte causes the host any harm; in fact, there is no competition for resources between the two plants at all. The host is merely a "prop" to hold the epiphyte off the ground. With tropical forest destruction occurring at an alarming rate worldwide, the available hosts for any epiphyte (which are incredibly common in the tropics) is becoming a scarcity. The sign in the top photo says "do not touch the plants," and there was actually a representative from the nature preserve that was watching all of the tourists like a hawk to make sure no one touched anything. Aside from staghorn ferns, there were incredibly rare orchids (not in bloom, unfortunately) that were also planted there. If someone had of unknowingly picked them, they might have successfully wiped out the only remaining viable population. That might seem like punishment enough, but that would also come with jail time in most tropical countries. Don't pick the plants!

All ferns are vascular plants, which means they contain phloem and xylem to transports nutrients and water throughout the plant (unlike mosses, liverworts and hornworts, which are non-vascular; you can read about the only profiled non-vascular plant, Marchantia, on my blog so far HERE). They reproduce through the production of spores, not seeds, which need to find a suitable habitat to germinate or else they die. Seeds were a great invention by the plant world; this allows plants to create offspring in less than ideal circumstances and let them go dormant in the soil (or a crevasse of a tree, on a leaf, in a compost pile, etc.) until conditions are suitable for germination. Seeds also have nutritive tissue packaged inside them which gives the plant embryo a sugar, protein and fat kick-start which spores can't provide.