The orchids.

Orchids or orchidaceae (scientific name Orchidaceae) are a family of monocotyledonous plants that are distinguished by the complexity of their flowers and by their ecological interactions with pollinating agents and with the fungi with which they form mycorrhizae. The family comprises approximately 25,000 (some sources report 30,000) species, and perhaps another 60,000 hybrids and varieties produced by horticulturists, making it one of the most species-rich families among angiosperms.

They can be recognized by their flowers of strongly bilateral symmetry, in which the middle piece of the inner whorl of tepals—called labellum—is deeply modified, and the stamen or stamens are fused to the style, at least at the base.1 Orchids constitute an extremely diverse group of plants, which can range from a few millimeters in length (certain species of the genera Bulbophyllum and Platystele) to gigantic aggregations weighing several hundred kilograms (some species of Grammatophyllum) or have lengths of up to 13, 4 m, as is the case of Sobralia altissima, an orchid recently described in 1999 in Peru.23 Similarly, orchid flowers vary in size from less than 1 mm and hardly visible to the naked eye (Platystele) to the large flowers from 15 to 20 cm in diameter in many species of the genera Paphiopedilum, Phragmipedium and Cattleya to the 76 cm flowers of Phragmipedium caudatum.

The fragrance of its flowers is no less variable, from the delicate aroma of Cattleya to the repulsive stench of the flowers of certain species of Bulbophyllum. They are found in most parts of the world, although they are especially abundant in the tropics. However, their ability to adapt has allowed them to conquer countless ecological niches, from the driest and hottest on the planet to the wettest and coldest since they are literally distributed from the polar regions to the equator. The family has been recognized by classical plant classification systems, such as the Cronquist system, as well as more modern ones, such as the APG II classification system and the APG III classification system.

Orchids are herbaceous, perennial (rarely annual), terrestrial or epiphytic plants, occasionally climbing, sometimes saprophytic or, rarely, mycoheterotrophic. Regarding epiphytic orchids, it is said that they can become eternal. In fact, in nature, their survival is linked to the life of the tree that supports them. Plants collected in the mid-19th century are known to still be growing and flowering in many collections.

The stems are rhizomes or corms in terrestrial species. In epiphytic species, on the other hand, the leaves are thickened at the base, forming pseudobulbs that serve to store water and nutrients and that are generally covered by membranous leaf sheaths that dry with age. There are two basic types of growth within the family: the sympodial type, which gives rise to multiple stems, and the monopodial type, which gives rise to a single stem.

The sympodial type of growth is the most common within the family. Most of these orchids have pseudobulbs that function as reservoirs of water and nutrients. The plant holds the pseudobulbs almost vertically and the subsequent growth and development of new stems occurs horizontally, between the pre-existing pseudobulbs. Each new pseudobulb originates at the base of the previous ones and, with its growth, gives rise to new leaves and roots. The leaves originating from each pseudobulb can last many years, providing nutrients for the entire plant, until they turn brown and die. Even without leaves, each pseudobulb continues to support growth and supply the energy necessary for the growth of the rest of the plant and for flowering. Some examples of orchids with this type of growth are the Cattleya, Dendrobium and Oncidium genera.

Orchids with monopodial growth, unlike the previous ones, have a single main stem that grows erect and indefinitely from the center of the plant. Normally, the stem grows upward and roots originate at the nodes, which grow downward. The plant, as it grows, loses the lower leaves as new leaves form at the upper end. Some species of orchids with this type of growth are those belonging to the genera Ascocentrum, Phalaenopsis and Vanda.

*Continues in my next article 🌸🌸