Philip C. Tomlinson       © 1998

CATTLEYA ALLIANCE
CATTLEYA
BASIC CULTURE

INTRODUCTION

Cattleyas are one the most popular of all the orchids grown around the world , and to a lesser extent, in this country. There are many books devoted to just these plants, Quite widely available from specialist orchid nurseries, they can also often be found in garden centres and similar outlets. They produce attractive and distinctive flowers - the famous 'chocolate box' orchids, many of which are long lasting

The notes are based on bark culture, in a glasshouse or in the home. Culture under lights is not covered, although the seasonal cultural tasks etc are still relevant.

Amongst the uninitiated orchids are commonly thought to be delicate plants requiring expensive growing facilities. Cattleyas include amongst their numbers those which are strong robust plants capable of surviving quite difficult conditions, although, of course, their growth and flowering will be much better and more assured when their relatively simple basic requirements are provided. There are, however, some cattleyas which are more delicate and which require additional care, but there are plants attractive to all covering a wide spectrum of growing skill and conditions. Most cattleyas require a glasshouse or protected growing area for optimum results at least in this country (New Zealand), although the facilities provided do not necessarily have to be extensive or expensive. As a group they do require some additional warmth and heat as compared with cymbidiums, for example, but this effort is more than repaid by their spectacular and colourful flowers. They can also be grown in the home, in the bathroom, lounge or kitchen, on the refrigerator or TV or other suitable shelf, provided additional humidity is supplied through the use of a gravel tray or similar.


Cattleya bowringiana

The cattleya alliance is a large one which include a number of popular and widely grown genera - laelia, brassavola, schomburgkia, encyclia and epidendrum, barketria, sophronitis to name the most popular ones. While this page will cover the cattleyas themselves, information specific to the other genera mentioned can be found on their respective pages.

In a general guide such as this growing information relevant to all areas cannot be discussed. What will be attempted is to detail the general growing criteria, and the reasons for the various recommendations. This should enable any individual to ascertain the general growing and seasonal requirements. It is, however, recommended that anyone new to growing orchids, or someone moving to a new area, contact a local grower to ascertain specific local growing advice. In particular the members of local orchid societies will be happy to assist with the local information. Joining a local society is the ideal way to make new friends and to obtain the most assistance, but speaking to growers at the local society orchid shows held throughout the country, or even just obtaining the name of a local grower who may be able to assist over the phone may be all that you require. Orchid growers are renowned for their enthusiasm for speaking about their favourite plants, so never be afraid to seek assistance.

Most of the cattleyas grown have been developed from plants native of the America's, especially Central and South America,. The various species come from a considerable range of habitats, from the high mountains to sea level. Thus there is a range of both cool and warm growing plants to select from, although the majority do require intermediate temperatures. It is important to note, however, that many cattleyas come from lowland coastal regions, areas that naturally have a warmer climate. Some of these habitats are very dry coming from the desert prairie savanna habitat.   Others are native of the intermediate foothills rainforest experiencing the summer monsoon.  


Potinara Rainbow Bay

Some cattleyas, especially the unifoliate (single leaved) labiate species and hybrids, have very thick heavy leaves. Such leaves have additional water storage cells, and a very heavy cutin layer to conserve any water they contain. Accordingly they are able to survive the periods of drought which often affect their habitats. As a general rule, those plants with heavy thick leaves must not be over watered i.e. watered too frequently. You must ensure they are allowed to dry out between waterings otherwise problems can occur. Plants which have thinner softer leaves are the opposite; they should not be allowed to dry out between waterings. Always look at the plant and try and read what it is telling you about its natural habitat conditions. If you can read the plant in this way you will have greater success.

Most of the plants are epiphytes, i.e. they grow on the branches of trees, although unlike parasites, do not obtain nourishment direct form the host tree. Some grow on the ground as terrestrials, in a thick mat of humus, moss and leaf detritus. There are a few that are lithophytes, plants that grow on rocks. Of importance to their culture is the fact that their roots are exposed to the atmosphere; they require plenty of moisture, but their growing environment must not retain excessive water. For this reason the use of normal garden soil will be disastrous, and the use of specialist bark and peat growing media is required. The growth habit is sympodial, they grow sideways with new growths developed in the spring, which mature over the next 9 to 12 months, produce a flowers, which then develop one or two new growths themselves to continue on the process.

Within the cattleya genus there are two general groups. The first bears a single thick heavy leaf on each pseudobulb. This group generally (but not exclusively) bears a single large spectacular flower, and is known as the unifoliate or 'labiata' group, after the species Cattleya labiata. The second group ( the bifoliate) are generally characterised by tall slender pseudobulbs which bear some 2 or 3 thinner textured leaves and which generally have a cluster of flowers in a bunch. This group is centred in Brazil, and come from seasonally variable habitats. The climate shows quite cool winters, during which the plants remain dormant. During this period of no growth the plants can be kept cool. The climate is also dry and bright. With the onset of the spring, new growths will be broken. Temperatures are warmer and there is increased rainfall. The sunshine will be brighter, but with more foliage on the trees and the onset of the more overcast summer monsoonal conditions, light levels are reduced. Summers are warm and moist. The autumn experienced gradually cooler and drier conditions, during which most of these plants mature. The seasonality must be allowed for in our culture for success with these plants.

The first group of unifoliate cattleyas include species such as labiata and its numerous forms, dowiana, rex, mossiae, lueddemanniana, warscewiczii, trianae, perceviliana, gaskelliana, warneri, lawrenceana, and maxima. The bifoliate cattleyas include dormaniana, velutina, bicolor, aclandiae, schilleriana, violacea, walkeriana, braziliensis, nobilor, granulosa, schofieldiana, porphyroglossa, elongata, amethystoglossa, leopoldii, guttata, intermedia forbesii, loddigesii, harrisoniana, tenuis and non Brazilian species skinneri, deckeri, aurantiaca, and boweingiana.


Cattleya Grodsky's Gold X mossiae

Plants can be purchased in flower relatively inexpensively, and this is generally preferable for new growers. Small plants can take 4 to 6 years from seed to reach flowering size. You can grow from seed yourself, but contrary to the usual garden plants, seed must be sown and germinated in sterile containers which new growers can find difficult. Also, the establishment of plants from the flasks, while an interesting challenge, can be difficult for those without experience of orchid growing.

Seedlings can be purchased, which will produce variable flowers even where the same parents are involved, reflecting the variation and quality of the parents. A group of seedlings can be interesting to grow, as you never really know what you are purchasing, and the variation in individual plants gives an added interest. Most orchids will, however, be obtained as divisions. Mericlones, which have been a major factor in the improvement in the quality of many orchids will be an important type of source material. Mericlones are a laboratory produced identical reproduciton of the source material, and beasue they can be produced relatively cheaply, enable the widest distribution of high quality material.

The general growing temperature groupings widely noted for orchids can be summarised as follows:-

 Temperature Conversions
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Temperature  O F:
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TEMPERATURE GROUPINGS

  Optimum range targets  

All in degrees Celsius  

 
Temperature groups WINTER  SUMMER 
.         DAY NIGHT DAY NIGHT
COOL  10-15  7-10  15-18  7-15 
INTERMEDIATE  18-20  12-15  18-25  15-18 
WARM 20-25  18-20  20-25  18-20 

To assist readers to find paragraphs of particular interest, key words in the paraghraphs have been marked in bold type. This should enable particular items of interest to be quickly found.

CULTURE BASICS

Before anyone commences growing any plants, it is important to remember that successful growing requires -

* suitable temperature levels

* an adequate supply of water

* plenty of fresh moving air

* suitable light levels

* and a suitable level of essential plant food

Always consider your culture in totality and in relation to the above factors. If you are experiencing growing difficulties it is well worth remembering the above requirements and looking at your culture on this basis. The specific cultural recommendations will be written with the above in mind, and should provide the answers to the main requirements. Observation of your plants and their growing conditions is always the precursor to success.

Remember that it is not what you do well that controls your growing success. Rather it is that which you do worst. If, for example, you do everything else right, but forget to water the plants correctly, then the plants will only grow to the extent allowed by the limited water supplied. If you then correctly water the plant, growth will then be limited by the next factor not supplied to the optimum levels. The following will initially concentrate on the cattleya genus itself and in particular the single flowered single leaved 'labiate' cattleyas, with supplementary notes for the other genera in the alliance later.

SEASONAL CULTURE


Cattleya Bonny Houck

The following cultural notes are focussed on cattleyas, but are also generally applicable to other plants in the alliance. At the end of the notes some specific cultural notes will be given on any particular requirements for the other plant groups.

Most of the cattleya plants are native of the monsoonal foothill habitat, and detailed information on this habitat, and further cultural recommendations can be found on this page.

SPRING

  • · This is the time of the year that you will be enjoying the fruits of your years growing, plenty of flowers. Cattleyas produce their flowers for much of the year, but with some seasonal peaks. If you select a number of plants carefully, you can have flowers for most of the year. If you are missing a great display now or through the year, now is the time to review your culture over the past 12 months, and, if necessary, to seek advice.
  • · The natural starting point is the time of commencement of new spring growth, especially the start of new root growth. With some the onset of growth is spectacular after winter dormancy; with others it is not so immediately noticeable. For those plants grown on slabs, it will be more readily apparent, but for pot cultivated plants it will not be so obvious. If you observe the plants, the signs of new activity can be seen. In this country growth will commence earlier in the north than the south, so you will need to observe your plants.
  • · The flowers for most of the plants will be enjoyed while they remain on the plants, and will remain in perfection for some considerable period in many cases. Many of the plants are compact and attractive in themselves, and they still make attractive displays inside while displaying their flowers still attached.
  • · If you have experienced few flowers, it is worth remembering that most cattleyas should experience a 8 to 14 degree Celsius temperature differential between the day and night temperatures for proper growth and flowering. Also, most cattleyas are photoperiod as well as temperature sensitive. Their flowering is determined not only by the day length they experience, but also by the seasonal temperature variations.
  • · Follow the general temperature recommendations given earlier. However, note that most of the yellow cattleyas (those with Cattleya dowiana in their parentage generally require higher temperatures all year than is normal for the genus. On the other hand most of the smaller growing red cattleya and related colour hybrid shades enjoy slightly lower temperatures than the standard hybrids. These types only obtain their best colour when grown cool with relatively bright conditions. This applies especially to any hybrid with sophronitis species in its ancestry.
  • · With the removal of the flowers and new growth commencing, now is the time for repotting
  • · Repotting, the replacement of the growing material, is required when -
    • · - the plant has grown too large for the existing container or
    • · - the existing potting material has broken down and must be replaced.
  • · Most plants require repotting every second or third year as the material gradually breaks down thought normal bacterial and fungal decomposition. Small plants will respond with increased growth with more frequent repotting - say every six to nine months if some supplementary heat can be provided, otherwise every year. .
  • · Many other garden plants can be potted on i.e. placed in a larger container when they have outgrown their existing one, with new potting mix added to fill the new larger container. With orchids this ‘potting on’ is not generally recommended. It is preferable to replace all the potting mix to give it a fresh start.
  • · Cattleyas are repotted in a variety of growing mixtures, which are generally bark based. It is also possible to mount plants on branches or slabs of tree fern or similar material. A good potting mix must be free draining but at the same time retain moisture. For most of New Zealand bark based mixes will be the best, most readily available and least expensive, and such a mix will also usually be the most appropriate in other areas. The watering habits of the grower can also influence mix selection. If you are compulsive with the watering hose, then you will require a more open free draining mix. On the other hand, someone who neglects watering, or is away from home for periods, may prefer a finer mix, one able to retain water longer. The size of the growing container is also relevant, smaller pots tend to dry out quicker that larger ones. When selecting a suitable potting mix consider the conditions over the whole of the year, not just a particular season. If summers are hot and dry, you may think a moisture retentive peat mix may be best, but if the winters are really cold, the wet mix under cold conditions will often lead to root death and in such situations you may be better to utilise an open mix but have to water more frequently during the summer. This is a typical example of fine tuning requirements to a particular locality.
  • · It is important that cattleyas are grown in an open mix as such mix duplicates the natural habitats of most of the plants, which grow through distinct wet and dry cycles. Plant of air must be able to reach the roots as naturally these are usually freely exposed to the atmosphere.
  • · Chopped pine bark is generally the most widely recommended potting mix. This is relatively cheep, readily available, easily handled, and has a reasonable life (although quality can vary). Generally medium to coarse bark should prove the most suitable. This comprises pieces 5 to 15 mm in diameter. Generally the mix should have the dust removed. The placing of a few larger pieces at the bottom of the container can increase drainage. Obviously for small plants a finer mix can be utilised. Commercial mixes are available, although you can make your own if you know what you are doing. Commercial mixes also usually have fertilisers added which will last 6 to 9 months, and so can be more convenient.
  • · Plants must be firm in the mix, but not too tight. You should be able to lift the plant in the pot by its foliage and not cause it to fall out of the container 9 times out of 10. If most do, place the potting mix more firmly; if none do, do not place the mix so tightly.
  • · If the division lacks roots you may have to stake the plant in the container. If it flops around the new developing roots can be easily destroyed, so you need to be able to stop this occurring. Place the stake near the rhizome, preferably as repotting is being done so you can see where the roots lie and ensure they are not damaged. Often a tie around the base of the leaves to a short stake is all that will be necessary to secure the plant satisfactorily. If you have to stake an already established plant, avoid the outside of the container, as many roots circle the inside of the container. Placing labels against the inside of the pot can also damage roots.
  • ¨ After repotting is completed, keep the plant in a warm shaded position and keep on the dry side for 2 to 3 weeks. It is desirable to mist the plants to avoid unnecessary stress but you need to stimulate new root development as quickly as possible. The aim is to get as strong and vigorous growth as possible which reaches maturity as quickly as possible to ensure maximum flowering the following year.
  • · For optimum results, any repotting and dividing must be completed at the correct time. Usually this is in the spring, must before new growth commences. Once the new roots can be seen, repot them, If they are longer than 20 mm they can be easily damaged, causing their death, which can risk the whole plant. Re-establishment will be quickest when the new roots are actually elongating. The time of repotting is especially important with the bifoliate cattleyas. The initiation of the new roots on the developing pseudobulb is especially late with may of the bifoliate species, often not occurring for some 4 to 5 months after the new growth is initiated. At this stage the growth will be quite tall. Repotting too early can endanger not only the new growth, but even the whole plant. Always repot these plants by looking at the new roots being formed, and not just at the size of the developing growth. As an alternative to growing in pots, many respond well to be mounted on slabs. Not only does this add interesting variation to a collection, but many respond vigorously to this form of growing.
  • · Suitable mounts are pieces of cork bark or cork branches, thin slabs of tree fern, suitable pieces of driftwood or tree branches - especially citrus and manuka. Slab mounting is especially suitable where higher levels of humidity can be maintained.
  • · There are a number of ways of mounting plants are available -
    • · 1 A cut can be made in the mount, the plant carefully wedged into this.
    • · 2 Usually the plant is tied on by
      • · a thin monofiliament fishing line or
      • · b thin copper or plastic covered wire, or
      • · c a piece of nylon stocking
    • · 3 Some plants can be glued directly onto the mount with a non toxic adhesive.
  • · A pad of sphagnum moss over and under the roots can aid establishment, providing local moisture and humidity, although this can be removed once the plants are established on the mount.
  • · Slab mounted plants will generally appreciate a higher level of humidity during the warmer summer season, but also generally all year if this can be provided.
  • · When mounting, consider the growth habit of the plant. Some have a long root run, so mount at the top so there is plenty of room for the roots to grow. Others have a climbing scandent rhizome, and such plants should be mounted lower down on the mount to allow this growth to occur. Remember to ensure the plant is firm on the mount. If it is loose, any movement that occurs can damage or even destroy the developing roots, which can set the recovery and re-establishment back several months.
  • · Repotting is usually only done in the spring, ideally just as the new root growth commences, before the new roots are too long and which may be damaged during the repotting process. You can complete in early autumn after the main growth period has finished, but the plants then do not have the same time to re-establish before the winter. Only repot at other times of the year in emergencies.
  • · When you purchase new plants, it is often desirable to repot them into a new fresh mix or remount them as this makes for easier watering. Plants in a variety of growing media can make watering difficult as different mixes dry out at different rates. Repotting also gives you the opportunity to check out the health of the plant generally, but especially the root system.
  • · During repotting you may divide the plant if it has grown into a large multi growth specimen. Remember, however, that a large specimen can be spectacular.
  • · When you divide a plant, remember that a flowering plant comprises 3 to 4 mature pseudobulbs. Smaller divisions take several years to recommence flowering.
  • · Old leafless back bulbs are often removed from the plants during repotting and when dividing a plant. In some cases these can be coaxed back into growth when repotted in a small pot on their own. They can also be placed in a closed plastic bag containing damp sphagnum moss and kept in a warm shaded position. A number will break into growth again in some months, and once they have developed roots some 25 mm long they can then be removed from the bag and potted up in the normal way. Only experience will tell you which species and hybrids can be propagated in this way, but 'nothing ventured, nothing won'.
  • · Remember to re-label all plants, and divisions. A plant without a label and name looses much of its value. While a species plant can be re-identified, with thousands of man made hybrids their identification is usually impossible. The plant label should include the date of repotting.. Labels can be marked with a good permanent marker pen, although a HB pencil will often be the most long lasting. Remember to check the labels periodically as they can fade over time. In addition to the visible label, it can be beneficial to include another buried in the potting mix as insurance in case the other is moved or lost.
  • · Always try to have plants with strong healthy root systems, as these will perform the best. When purchasing plants one of the main criteria is that they have strong healthy roots, such plants will re-establish in their new homes so much quicker and earlier.
  • · With warmer conditions gradually becoming the norm during the spring, pay increasing attention to watering. Allow the top of the mix to dry out somewhat before watering. When you do water, apply plenty, ensuring there is a free row out of the drainage holes at the bottom of the container. Water the plants once, then do it again a few minutes later. Bark mixes in particular can be difficult to wet once they become dry and a double application ensures they hold maximum moisture. 0ver watering is watering too frequently, not a reference to the amount applied at anyone time. How often watering is required depends on the conditions where the plant is growing, the temperature, and the nature of the potting mix - coarser mixes dry out faster then finer ones. In early spring, for large plants, once every 10 days or so may be frequent enough. Smaller plants, and under warmer conditions, more frequent applications will of course be required. Plants on slabs often require more frequent watering.
  • · As the sun becomes stronger towards the summer, increased shading may be required - the use of 30 % shade will generally be appreciated. Brighter light can lead to increased flowering, although such conditions can lead to unsightly burning of the foliage. If you grow under bright light, increased ventilation and air movement is desirable, and if humidity can be increased problems should be minimised. The use of a fan running all day and night can be of significant assistance in reducing burning. Leaves should be of good texture, and of a light yellow green colour; dark green foliage generally indicates too little light is being provided.
  • · Shade requirements can be summarised as follows in general terms.
    • · NIL = full sun
    • · MEDIUM = on a bright day, a hand placed between the sun and the plants casts a clear but not bright shadow (30%? shade)
    • · HEAVY = hand shows only a faint shadow (say 50%? shade
    • · Actual requirements will vary depending on the level of light experienced in the particular locality.. Seek local advice from a local grower or local orchid society for locally recommended advice
  • Generally cattleyas require good light to flower property, and if a plant is not flowering often increasing light levels over some weeks (to avoid burning) will have the desired result.
  • · Plants growing strongly will benefit from the application of fertilisers. When bark mixes are utilised, a high nitrogen fertiliser is generally considered appropriate. Once growths have matured, reduce the nitrogen component, and increase potash. Wither use liquid or dry fertilisers, applied at the rate of around half the manufactures general garden recommendations. A little fertiliser often is often the best.


Cattleya harrisoniae

SUMMER

  • · The growing season will now be well under way. Root action will be strong and the new growths should be developing strongly.
  • · With temperatures now increasing towards their maximum, the plants should be in their summer homes. As most cattleyas will be grown in a glasshouse all year, increased attention to shading and ventilation is critical.
  • · Plants can be kept under 30% shade generally, although some sections as noted respond to more sun.
  • · Do not crowd the plants too much as plenty of fresh moving air is essential. The use of fans will be beneficial.
  • · Increased watering will be necessary. As this is the main growing period, do not stint this work as you do not want to give the plants any check to their active growth. If you are going away on holiday try and get someone to water the plants, but make sure they understand what is required, as if they are not used to orchids they could cause damage, even loss of plants. In a glasshouse, the use of misting sprays over and under the benches can be beneficial by increasing the humidity levels.
  • · Most cattleyas are relatively pest and disease free. If a continuing problem does arise, look closely at your culture as many problems can be solved without resorting to the use of chemicals. . If any pests or diseased do become established, approach your local garden center for specific advice on products and how they should be most effectively applied. Check that the products are suitable for orchids, as some are sensitive to some products. Always test on a few spare plants first for safety before applying to all the collection. Remember all sprays are poisons and must be used with care.
  • · Around mid summer, reduce the application of nitrogen fertiliser and increase the application of potash.

AUTUMN

  • · With the development of cooler autumn conditions, any summer shading can be gradually removed.
  • · As conditions cool, reduced watering will also be appropriate. Avoid overhead watering, especially if cooler conditions are anticipated, as water lodging in the growths can lead to their rotting. Generally it is desirable to always water early in the day to ensure the plants dry before nightfall, especially in the autumn.
  • · Continued fertiliser applications are appropriate, but adjust the amount of application to the amount of growth taking place.
  • · With more flowers appearing, continue staking plants, using cane or wire stakes. If you are using wire, turn the tops over and watch your eyes don't get poked out when working with the plants.
  • · Bring the plants into the home and enjoy the flowers.
  • · When moving plants, ensure they are returned to the same orientation to the light source. Turning a plant can cause the flowers to become twisted, spoiling an otherwise attractive presentation.
  • · If you are growing without heat under cool conditions, tend to keep the plants drier than usual, as wet cold conditions are often fatal to roots.
  • · Minimum temperature requirements for the various plant groups should be followed. Mature plants can be grown cooler, but growth will be reduced. The growth of small plants will be facilitated if temperatures some 5 oC. higher than is indicated for adult plants is maintained, ensuring the period to flowering is reduced to as short as possible. Ensuring minimum temperatures are met will result in overall better growth and flowering. If heating is required, ensure all systems are 'go' before the winter, as you do not want to be caught out when a sudden cold spell occurs. Remember that once supplementary heating comes on, the atmosphere can dry out quite quickly, and careful extra misting of the plants may be required.
  • · Avoid giving the plants a check in their growth for any reason, as once this occurs it can take quite some time for optimum growth to be re-established.
  • · Small plants in particular appreciate some additional warmth, and the use of bottom heat provided by a heat board or warming bed can be most beneficial and economical way of ensuring their maximum growth to reaching flowering size as quickly as possible.
  • · As plants mature, adjust watering as appropriate, and increase the amount of light to the plants


Sl My Little Pumpkin

WINTER

  • · Adjust the amount and frequency of watering to the conditions being experienced. Maintain watering if it is warm and sunny. If cold dull days are prevalent, reduce the amount and frequency of watering as many plant roots can be lost under cold wet conditions. If in doubt it is better to err on the dry side.
  • · Adjust the amount of fertiliser being applied to the amount of plant growth taking place. If a particular plant is dormant then it is a waste of money to apply a lot of fertiliser. Where there is reduced growth, apply but at reduced rates and frequency.
  • · Spotting and insect damage can affect flowers. With lower evening temperatures, humidity will increase, especially after a warm day. Good ventilation and air movement is essential.. The use of fans, especially in a glasshouse, is beneficial. Water on flowers can cause spotting, and therefore overhead watering at this time of the year is not recommended. Slugs and snails can also cause damage, and may need to be controlled.
  • · Now is the time to enjoy your growing success. Taking some time will ensure your growing efforts are presented to their best.
    • · - ensure the pot is clean, with all dirt moss removed
    • · - remove any dead leaves and old leaf bases from the pseudobulbs
    • · - clean the foliage of any old spray residue, dirt, dust etc. Remember when wiping down the foliage, hold the leaves by their bases and wipe from the base to the tip. The leaves, especially from the newer growths, can be easily pulled off if care is not exercised.
    • · - ensure the plant is correctly labelled, especially if you are going to present it at a show.
  • · .The plant has expended considerable energy in producing the flowers. The best results will only be obtained if the plants are healthy and in good condition. If there is any doubt regarding the vitality of the plant, the flowers should be removed quickly. It is generally desirable that flowers be removed form the plants 2 to 3 weeks after opening.

Remember, growing orchids is all about enjoying your plants and sharing your growing success with friends and family.

Good luck and good growing.

The information on these pages should be read with the general recommendations for cattleyas on this page.


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