Thursday, November 29, 2012

Dendrobium keiki, What causes them to appear?

Dendrobium harveyanum keiki producing a second cane, because it has substantial
roots it can be removed with little fear that it wiil die.

Keikis from unbloomed stem of Dendrobium Yellow Chinsai, probably caused
by too much nitrogen in the fertilized applied late in the growing season

Dendrobium anosmum keikis, these are tiny and have little green tissue to support
independent growth removing keikis this size is not adviced.

Dendrobium anosmum keiki, this plant has a good size for a keiki and a significant growht of roots.   It can be removed with confidence that it has enough reserves to start growing idenpendently

These Dendrobium anosmum keikl have three canes with means they are over due for removal
from the cane, the original cane has decayed completely.

Dendrobium primulinum keiki, although on the small side for a keike the fact that it has two canes
will help this plant adapt to independent living without too much trouble.

Dendrobium fimbriatum oculatum keiki.  This keiki is quite large and can be treated
right away like an adult plant onece it is removed from the cane.

One characteristic of some Dendrobium species is that they have the capacity to produce plantlets from the meristematic tissue that lies in the form of small buds along the sides of the canes of the adult plants.  Most of the year these buds lie dormant, but if they are activated by hormonal changes in the plant they can turn into floral stems or into little plantlets.  In the hobby these little plants are known as keiki, this is the Hawaiian word for baby.  I will use the term keiki to refer to this form of propagation on the rest of this article.  Keikis are plantlets produced vegetatively by the mother plant, it is an asexual type of reproduction which means that the little plants will be exact copies of the mother.
 The frequency of keiki production varies wildly in the Dendrobium genus.  Some species will never, or only very rarely produce them, I have yet to see a keiki in a plant of Dendrobium farmeri or Den. secundum.  In other cases some plants will produce keiki and others of the same species will not.  This is my experience with Den. harveyanum, one plant has produced several keiki while another has never produced them.   Some species will almost always produce one to a few keiki from older canes, an example of these are Den. anosmum, Den. cucullatum and Den. primulinum.  In the extreme of keiki production Den. crumenatum and Den. kingianum produce them frequently and sometimes abundantly. 
There are several circumstances that can stimulate the production of keiki.  A relatively common occurrence is the production of keiki instead of flowers.   Normally canes will not produce keiki in their first year, before they have bloomed.  If a mature cane produces keiki instead of flowers when its blooming season comes around, this means something has disrupted the sequence of metabolic processes that produce the hormonal changes that turn the resting vegetative buds into floral buds.  In Dendrobium descended from Den. nobile and related species, if the plant is given a fertilizer with a high nitrogen content during the latter part of the growing season or the resting plant experiences too high temperatures, this can “short circuit” the blooming response and then it can either not bloom or it can produce keiki where blooms would have been expected.    I have seen plants produce keiki all along the cane where flowers should have been.  In rare cases a plant can both produce keiki and some flowers.   A few days ago a friend showed me one of his Den. nobile hybrids where the plant had produced keikis instead of flowers and then some of these keiki had produced a single flower from the tip of their tiny canes.
In many Dendrobium species the sudden production of keiki by a plant on canes young and old is a signal of significant root loss.  I have frequently observed this on Dendrobium species from the Spathulata section and on hybrids descended from Sphatulata/Phalaenanthe section.  These hybrids are produced by the millions and are commonly sold on Walmart, Home Depot and other stores because they travel well and their flower sprays last for weeks in good condition even in hot weather.  The problem with these Dendrobium is that most the people that buy them often now virtually nothing about their growing needs.   When these orchids are repotted they are frequently put in dense bark mixes that are kept wet.  If the mix is so dense and soggy that it doesn’t allow oxygen to reach the roots, the roots die.   The one common indication that the roots have died is the complete defoliation of the plant.  That is all canes, young and old shed their leaves due to the loss of the capacity for water uptake.   By the way, it is normal for the older canes of many types of Dendrobium to be leafless, it is abnormal for a cane of the year to lose their leaves, particularly in the evergreen types that are common in the retail market.  If the plant is cared for well, it might start growing in its season and if it has a number of healthy canes it can even produce a reasonably large mature growth that will in time produce a new root system.  But if, the loss of roots has been accompanied with the loss of the lower vegetative buds, the plant can produce keiki from the top of the canes.  I have seen plants that have lost the lower vegetative buds because the owner buried the base of the stem under the potting media and the new growths have succumbed to rot.  By the way, sometimes a Dendrobium will produce a new cane from a bud that is located slightly higher in the stem than previous growths, this is not a keiki, as canes produced this way can develop normally to full size.  This sometimes happens when the buds at the base of the stem are lost.
Keiki produced at the top of the canes varies hugely in quantity and quality depending of the ancestry of the plant.  I have an antelope Dendrobium (of the Spathulata section) called Percy’s Passion.  This plant lost its roots and produced a single very large keiki that is for all purposes a small adult plant.  This keiki has even bloomed with a substantial inflorescence while still attached to its mother’s cane.  In these cases these keiki can be cut from their stem, potted and treated as an adult plant, they don’t need any special considerations.
On the other hand some plants will produce tiny keikis at the very tip of the canes.  These keiki are typically one to two inches long and depending on the parent species, can have a substantial quantity of roots or almost none.  Keikis that are smaller than two inches are a special case. They are much more fragile than those that are over two inches and might not survive being detached from the cane.  If they have few roots they will need care that addresses their particular needs and it may be more than the average grower might want to provide, also they will take a long time to reach maturity.  In my experience that hardiness and vigor of these tiny keiki vary depending on the species.  Keiki of anosmum, cucullatum, crumenatum and primulinum larger than two inches long, are quite hardy and survive very well if given appropriate care and an environment with high air humidity.  I have not been so lucky with small keikis of the Phalaenanthe section and of the “antelope” Dendrobium of the Sphatulata section.    In my experience keiki from these groups take more time to grow larger, produce roots more slowly and succumb to rot more readily.  Admittedly this is probably due to the particular environment in which I keep the keiki in my orchid growing area, some people elsewhere might have a different results.
I have observed that older canes sometimes produce keiki even in the absence of any of the issues that I have detailed previously.  My guess as to what causes this is that keiki production in older canes is probably related to the loss of the roots that are connected to that particular cane.  In these cases the plant still has a healthy root system in his younger canes and all the canes receive moisture from those roots, so this keiki production is not related to any distress from the part of the plant.  I don’t cut out these keikis until they have at least two canes and a significant number of roots. 
If a cane losses its vascular connection with the rest of the plant it can start producing keiki.  This may happen if part of the stem rots or is damaged.  If the base of the stem is buried in the media the death of the base of the stem might not be evident to the casual observer.  Also even though the cane connection to the vascular system is severed there still might be a substantial amount of dead but not decayed tissue holding the cane together with the rest of the plant.  When this happens to my pendent Dendrobium I may cut the cane in the part that has decayed and plant the keiki, still with the cane attached, in another container or mount.  This often makes a huge difference in the speed in which the keiki reaches adults size, as the piece of cane can provide, if large enough, with enough support to allow the keiki to produce a substantially larger new cane in its next growth phase.
Many growers propagate their Dendrobium using the capacity of these plants to produce keiki.   They cut the older canes into three to four node sections and lay them in sand that is kept moist.  I have seen this method producing satisfactory results with canes from “soft cane” Dendrobiums such as anosmum, cucullatum and with many of the types of the Dendrobium that are available at department stores and that are lumped in the literature under the denomination “evergreen”.

Tuesday, November 27, 2012

Dendrobium batanense, first blooming in my garden

I brought this Dendrobium back in the spring out of curiosity.  The plant adapted well to the climatic conditions in my garden and proceeded to produce several new growths that are still inmature.  The two largest canes, which were fully developed when I brought the plant were the ones that bloomed.  The canes are about two feet long but I am sure that as the plant get larger and older it will produce longer canes.  At the rate it is producing new canes it is entirely possible that in two or three years it will be an impressive specimen plant.  Unlike the flowers of the Dendrobium crumenatum which last only a single day, the flowers of batanense last three days.  The canes are flattened and hardly resemble a typical Dendrobium.   In this blooming there were only eight flowers, four in each of the two inflorescences.  This plant has been classified as an Aporum and as Ceraia.

Tuesday, November 13, 2012

Soft cane Dendrobium, end of growing season flowers

Dendrobium Bohemian Rhapsody, end of growing season flower

Dendrobium Bohemian Rhapsody, normal flower

Dendrobium anosmum, dark colored variant

Dendrobium anosmum var. huttoni
When the growing season ends for soft cane Dendrobium, the canes stop growing and produce a terminal leaf that is smaller than previous leaves.  But sometimes, instead of a terminal leaf, the plant produces one or more flower buds.  I have seen this happen in Den. anosmum. Den. pieradii, Den. loddigessii and Den. Bohemian Rhapsody.  These end of season flowers can be larger, differently shaped and brighter colored than flowers produced during the normal blooming season.  I don't know why this happens.  Some people, particularly those that have plants that have never bloomed, can take these flowers as a normal blooming event, but it isn't.  The flowers can sometimes be significantly different from typically shaped flowers, with a prominent raised area in the middle of the lip and pointy sepals. This variation can cause confusion as to the identity of the plant, on the part of growers whose plants otherwise have never produced flowers.  At times the flowers can be deformed or crowded in a bunch at the tip of the cane.  I don't find the appareance of these flowers a cause of concern as those of my plants that produce these flowers from time to time, bloom well when their blooming season comes around.

Saturday, November 10, 2012

Amazona ventralis, the hispaniolan parrot, in flight

This photo shows particularly well the belly area of a hispaniolan parrot.  The colors of the belly of the hispaniolan parrot can be used, along with other things, to ID this species.  One of the most distictive characteristics of the hispaniolan parrot is its white forehead.  The blue patches just behind the eyes are also useful to identify this species.  But it is the combined observation of the various traits that can give you the best confidence that you have correctly identifed this species.  In this photo you can see the white forehead, the blue patch behind the eye, the red patches in front of the legs and the red tail feathers.  This bird was photographed in one of the Rio Abajo aviary flight cages.  Hispaniolan parrots are used here as foster parent to eggs and chicks of the Puerto Rican parrot.  They are not for sale.  A selected few of these birds stay in the project their entire life where they receive exactly same care as the PR parrots.  Because the hispanionan parrots on ocasion are allowed to raise their own chicks, we produce a small number of birds of this species.  Some of the chicks stay in the program, most are sent to the Dominican Republic where a number of them have been released into the wild in El Parque del Este.  The USFWS sometimes keeps a few in the Iguaca aviary hispaniolan flock.

Here you can see the flight feathers.  The flight feathers are black and navy blue.  The colors of the flight feathers of the hispaniolan parrots is different from the color of the same feathers in the PR parrot.  In the PR parrot the flight feathers are turquoise.  This photo is of Ivan.  He if flying in the Rio Abajo bird hospital room.  Sometimes birds have to be hospitalized for a few days to receive treatments.  If they are alone in the hospital they can become depressed.  Ivan was born in May 2012, I plan to use him as a companion parrot to birds in the hospital.  Ivan is relaxed among humans and is familiar with the inside of office and the hospital.  I hope his generally unstressed demeanor among humans will be reassuring to birds in the hospital.  I have to add that infectious diseases are extremely rare in the RA aviary, almost all the birds that end up in the hospital do so because they need treatment for accidents or scrapes due to fighting .  After a few days of antibiotics they are sent back to their cages none worse for the wear.  In the case of a suspicion of an infectious disease we have a separate quarantine building that is used for this cases. 

Saturday, November 3, 2012

Puertorrican parrot goes bananas about its bathtime

This is a male of the species Amazona vittata vittata, the Puerto Rican parrot.  These birds greatly enjoy getting baths.  In the wild when it rains after a spell of dry weather the parrots become very excited and vocalize powerfully as they get wet under the rain.  In captivity the cages are designed so that the  birds can take baths whenever it rains, however a few will also eagerly seek getting wet under the water we use to clean cages.  From time to time we indulge them and allow them to frolick under the water stream.  As you can see in the video the bird is unabashedly enjoying the water.  These parrots are highly intelligent and we try, as much as it is possible in captivity, to enrich their enviroment with things they like. 
I want to make clear that this animal trusts me a great deal, birds that don't have a trusting relationship with their owners or keepers will not behave this way, some may even feel threatened when their cage is cleaned.  If you want to give your birds a bath like these make sure that the bird doesn't feels threatened, is in a familiar enviroment and that it can get away from the water stream at any time if it chooses to do so.
This particular male has been particularly fecund and a number of his offspring have been released into the wild as part of a program to reintroduce the species to parts of it former habitat where it has beene extinct since the early twenty century.