Oncidium, perhaps more accurately the oncidium alliance, are a group of plants from South America that span a wide range of habitats. Inside the oncidium alliance there are a number of genera that hybridize freely to create what we call intergeneric oncidium hybrids. These can come in all sorts of shapes and sizes but are generally characterized by large quantities of small to medium flowers borne on a branched stem that generally forms a Christmas-tree shape. The most commonly identified Oncidium are the yellow “dancing lady” type.
There are lots of orchid photos. I spent 16 days in country and managed to visit Sao Paulo state beaches, littoral plain and littoral mountains as well as the Mantiquera Mountains and up to Diamantina in northern Minas Gerais all by car with the well known Brazilian orchid expert, Marcos Campacci. The name may ring a bell as he is the describer of many new Brazilian orchid species such as Cattleya tenuis. He is also the editor of Boletim CAOB and Brasil Orqueideas, 2 major orchid publications in Brazil.
The den-phal type are warm growing year round and do, just by happenstance, bear flowers similar in appearance to the genus Phalaenopsis. They can be distinguished by plant habit (most Dendrobium have pseudobulbs that resemble tall canes) and flower shape. Den-phals have a spur at the back of the lip; some are more pronounced, others less. They are also borne on very strong upright to barely arching stems. Interesting to note, den-phals can rebloom on old canes.
This tribe is fairly large and consists of four genera — Dendrochilum, Pholidota, Chelonistele, and Coelogyne — and over 300 species. They are native to the tropical and subtropical regions of the Old World. Coelogyne is the most popular genus. Its orchids are characterized by a three-lobed lip that is concave at the base, and a hooded or winged column.
Avoid overwatering which leads to the demise of many more orchids than underwatering. Constant wetness will cause the roots to rot, which leaves the plant without a means for taking up nourishment which then causes the leaves to droop and will eventually kill the plant. The classic advice is to water the day before the plant dries out. If you have to let the plant go dry to figure out what a dry plant weighs, it will not kill the plant and will make you a better grower. Another measure is to use the pencil trick (the point of a sharpened pencil, when inserted into the medium, will darken with moisture if the plant has enough water). And, there's always the old standby - put your finger in the mix. If it feels wet, it is wet. If you aren't sure whether it is time to water, wait one more day.
The potting mixture, or growing medium, for a phalaenopsis orchid should be good at both absorbing water and providing airflow to the roots of the plant. Therefore, consider using media such as tree bark, coconut coir, clay pellets, perlite, pumice pebbles, and sphagnum moss, either on their own or blended together. If you live in a humid climate, choose a courser potting mixture that dries quickly and provides the best drainage. On the other hand, those who live in a dry climate should use a finer medium that will dry more slowly and hold more moisture.

Disa is a genus of beautiful plants with rather triangular flowers, often red. They require VERY different care than other types of orchids, so it's easy to kill them if you don't know what you're doing. In particular, they like it wet and should never dry out. The best-known Disa is Disa uniflora, which in South Africa is known as the Pride of Table Mountain.
The family encompasses about 6–11% of all seed plants.[4] The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). It also includes Vanilla–the genus of the vanilla plant, the type genus Orchis, and many commonly cultivated plants such as Phalaenopsis and Cattleya. Moreover, since the introduction of tropical species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids and cultivars.
The Lycaste orchid genus, similarly to its relative Anguloa, likes intermediate-to-bright light, intermediate-to-cool temperatures, and high humidity. The flowers look rather different, though; they are more-or-less triangular in shape because the sepals point outward while the petals point forward. These orchids are very fun to grow, and will thrive if you get their care right.

The den-phal type are warm growing year round and do, just by happenstance, bear flowers similar in appearance to the genus Phalaenopsis. They can be distinguished by plant habit (most Dendrobium have pseudobulbs that resemble tall canes) and flower shape. Den-phals have a spur at the back of the lip; some are more pronounced, others less. They are also borne on very strong upright to barely arching stems. Interesting to note, den-phals can rebloom on old canes.
Cymbidium carry tall stems with many flowers that have a more typical orchid shape. They are easily identified by their grassy leaves, and they readily form large clumps. Most common are the cool-flowering types, which need to experience a cooler winter (nights in the 40s for some time in the fall) in order to initiate flowering. Once the flowers open, they can last for up to two months or more, especially in a cool environment. These are very showy and rewarding plants, and a plant in a six-inch pot can carry three stems with 15 or more flowers each, depending on the type. 
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