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Along with other articles, columns and club updates, each monthly issue of the Henry Shaw Cactus Digest includes an article or two on members' favorite cactus and succulent species. The articles typically include photos and facts on the plants' natural origins and distribution, growing conditions, common and scientific names, care and cultivation tips, and helpful hints for encouraging flower production.
Follow the links below this month's offering(s) to enjoy previous Plants of the Month or click to read a sample of the HSCSS Digest in PDF format.
June 2019 -- Echinopsis
By Pat Mahon
In the cactus hobby, there seems to be one genus of easy-growing plants that reward us with gorgeous flowers in the spring: Echinopsis. Often taken for granted, most species and hybrids in the genus can quickly make specimen plants, are culturally forgiving and seem to give flushes of flowers.
Though mostly short-lived, echinopsis have elongated pedicels and large, trumpetlike flowers, whose presence typically dwarfs the plants. There is no shortage of hybrids available, with many colors and combinations. Once out of flower, echinopsis are practically indistinguishable from one another.
Instead of focusing on one species of Echinopsis, a sampling of its members can help us better understand the boundaries of the genus. First, Trichocereus is dead. The erroneous epithet is still used to describe trendy columnar cacti, but advances in taxonomy and technology (giving way to molecular systematics) have made Trichocereus and Lobivia victims of species delimitation shown to share a monophyletic relationship. Echinopsis is now the accepted generic name for these genera. A wonderful publication explaining the delimitation was published by Sofia Albesiano and Teresa Terrazas -- see link below.
Echinopsis are restricted to South America, where they grow in very similar habitats. The name Echinopsis is derived from the ancient Greek "Ekihnos," which is sea urchin; and "-opsis," which means appearance. They prefer sandy and rocky substrates, typically growing on hillsides and in crevices. All of the species have fibrous roots and should have a very well-draining substrate to avoid rot. Some columnar species previously referred to as trichocereus are sometimes found among brush in wetter habitats.
Most Echinopsis species seem to tolerate and enjoy lower temperatures during the winter, and must be deprived of water during their winter rest in order to develop flowers in spring and summer. Once winter dormancy is broken, echinopsis should be grown in warmth, which is thought to influence flowering.
Although the flowers are incredible, they typically last about 24 hours, starting to bloom in the late evening. In summer, ensure plants get some water toward the evening. Never water cacti on the bodies in full sun! Almost all Echinopsis species grow in full sun, but in cultivation, slowly introduce the plants to increasing light to avoid sunburn.
Most commonly referred to as the Easter cactus, this plant is usually on time with its name. A very globular cactus, it is fast-growing and pups freely. It is one of the most popular and easiest to grow species available.
Flowers may last around 36 hours indoors. Flower colors range from white to pink, and other colors are known. Native to southern Brazil, Paraguay, Uruguay, Argentina and Bolivia at elevations from 50 to 1,000 meters, this species generally represents what is commonly understood in form and shape for the genus.
Echinopsis ancistrophora subsp. arachnacantha (syn. Lobivia arachnacantha)
This smaller, clumping species is easy to grow and freely flowers if conditions are optimum. These are found with a myriad of colors and striping, and may include unknown or accidental hybridization. In any case, this species is highly recommended for any cactus hobbyist due to its small size, different-colored flowers and ease of cultivation. The plants are found in Bolivia and northern Argentina from 1,800 to 2,600 meters elevation.
Echinopsis pachanoi (syn. Trichocereus pachanoi)
Quite variable and distributed throughout the Andes, these columnar cacti are highly sought after for their attractive spines and dermal forms. They are found in higher elevations, from 2,000 to 3,000 meters. This is one of many former Trichocereus species that contains the psychoactive alkaloid mescaline.
Unless grown quite large, it is unlikely they will bloom in cultivation. Commonly used as a rootstock in grafts for slow-growing cacti scions, they are resilient to drought (or periods of non-watering) and exhibit fast growth. These plants are easily propagated by cuttings, and even when cut down can pup toward the base.
One of the most important discussions on Echinopsis concerns the boundaries that were delimited by including Lobivia and Trichocereus as a monophyletic treatment. Showing their close phylogeny, there are many hybrids incorporating former Lobivia and Trichocereus species.
If there is any similarity between these genera, it would be their ease of growth and maybe their prostrate branching, imbricate scales along the floral tube and subglobose fruits -- but who cares about that! If you are not growing any of these Echinopsis, be aware it is very high up on the list for beginners and those who just enjoy cacti flowers.
Cladistic Analysis of Trichocereus (Cactaceae: Cactoideae: Trichocereeae) Based on Morphological Data and Chloroplast Dna Sequences --
Trichocereus.net -- https://trichocereus.net/trichocereus-pachanoi-britton-and-rose-1920-echinopsis-pachanoi/
Echinopsis.com -- http://www.echinopsis.com
JSTOR -- Echinopsis, Lobivia, Rebutia: Where to Draw the Line --
Llifle Encyclopedia of Cacti -- http://www.llifle.com/Encyclopedia/CACTI/Family/Cactaceae/1041/Echinopsis_ancistrophora
Wikipedia -- https://en.wikipedia.org/wiki/Echinopsis_pachanoi
June 2019 -- Bursera
By Bob Williams
When researching Plant of the Month articles, you often read about the individuals after whom genera are named. The majority of the time, the individuals did field research for many years and wrote articles or books on particular genera.
The genus Bursera is named after Danish botanist Joachim Burser. He was born in 1583 and died in 1639. He became professor of botany and medicine at the Sorö Academy in Denmark. Burser traveled throughout Europe in search of plant specimens, which he arranged into a hortus siccus or herbarium. A hortus siccus is a collection of dried and preserved plant specimens arranged systematically in a book. Burser's 25-volume book was studied by many Swedish botanists, including Carl Linnaeus. An entire genus of plants only found in the Western Hemisphere is named after a botanist who only traveled around Europe.
There are 100 or so species within the genus Bursera. They are native to the Western Hemisphere from the southern United States south to northern Argentina, in tropical and warm temperate forest habitats. The most amazing fact is that over 80 of the 100 Bursera species are endemic to Baja California.
Burseras are woody plants. They can take the form of a shrub, growing to a height of 5 to 6 feet. Others are trees that can grow to a height of 80 feet or more.
Most of the species lose their leaves in the winter and have a dormant period. The leaves tend to be smaller. The bark of these trees is an attractive feature. It is richly colored and peels with age, giving the plants an aged look when grown as bonsais.
These species have been found to have medicinal uses. Bursera simaruba has been used to treat malaria and amoebic dysentery, manage leukemia, and for skin care. The gum of B. fagaroides is used to cure scorpion stings, insect bites and other wounds. The bark of B. roseana is used to treat wounds and sores.
A large number of Bursera species are known for their aromatic value. The sap of many species is made into a gum that is used as incense. Bursera graveolens is prized for its aromatic wood. The fragrance gets stronger as the dead wood "ages" for five years or more.
Burseras are relatively easy to grow and are often grown as bonsai with a caudex base. The plants should get at least a half day of sun, but look better if you give them a full day of sun. Growing them "hard" gives them the cool character of plants grown in the natural environment. You may need to prune these plants at least two times a year, cutting leggy growth back. This also helps to thicken up the trunk. Keep soil lightly damp between watering and fertilize as needed.
Burseras are best grown from seed, but can be started from cuttings. If your plants form seed pods, wait until the pods split and expose the brightly colored seeds within. The seeds stay attached to the stem, which makes harvesting easy.
Plant seeds in a well-drained soil, cover with about a half-inch of soil and keep damp. Germination will occur in seven to 10 days. Cut back on watering during the winter after the plants lose their leaves. Just a very small amount of watering will do. Although they are not winter-hardy, these plants can tolerate lower temperatures in the wintertime when placed in a cooler place in your greenhouse or where you put your other plants in the winter.
There are several species that are worth searching out and growing, including Bursera fagaroides, B. microphylla, B. oderata, B. schlechtendalii, B. hindsiana and Bursera epinata. Other species are also available.
Wikipedia -- https://en.wikipedia.org/wiki/Bursera
Island Herbs and Spices -- https://www.islandherbsandspices.com/product/bursera-simaruba-barks-medical-use/
Palo Santo -- https://www.palosantoshop.com/?s=bursera&product_cat=0&post_type=product
JSTOR -- https://plants.jstor.org/stable/10.5555/al.ap.person.bm000363480
Botanic Wonders -- Growing Bursera -- https://www.botanicwonders.com/Feature-Growing-Bursera.html
Llifle Encyclopedia of Trees -- http://llifle.com/Encyclopedia/TREES/Family/Burseraceae/Bursera/
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