PLANT OF THE MONTH Library     page 6
 serves as a reference library of descriptions of cactus and succulent plants 
designated as Plant-of-the-Month genera in the Cactus Chronicle newsletter. 

This section will grow as the web master adds information on past  and current POM selections.

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 Los Angeles Cactus and Succulent Society
 Los Angeles Cactus and Succulent Society


Weingartia - July 2016

Weingartia is a genus in the family Cactaceae, with species native to Bolivia and Argentina, in the Andes mountains of central and south Bolivia and northwest Argentina at elevations of 1600 – 3600 meters.

All species of the genus Weingartia were transferred to synonymy status under the genus Rebutia (Hunt & Taylor, 1990; Hunt, 1999, Anderson 2001).
-- Excerpted from Wikipedia

​See Rebutia and Sulcorebutia for more info.

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Yavia - January 2016

​Named for the Yavi department in Argentina where it was discovered.

Named in 2001, the genus Yavia is one of the most recently described genera in the cactus family. It was found growing at over 12,000 feet (3700m) elevation in a harsh, dry environment with very rocky soil. The single species is a small globular plant that consists primarily of a single stem, but may clump, especially when grafted. Ribs are present, but hardly noticeable beyond the rows of fuzzy-white areoles that feature very small reddish-brown spines. Flowers are pink with a short, thick floral tube.

Despite the recent discovery of this species, it is being rapidly propagated by enthusiasts and should become more and more available each year.
--- from

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Yucca - April 2014, June 2007

​ . . . the succulents of the month are several of the close relatives of Agave from the Americas. This group used to be called, the plant family Agavaceae, but today are considered part of the Asparagus family Asparagaceae. As most of you aren't interested in advanced taxonomy, let's just say these four genera are closely related to each other and share the characteristics of being woody and having grass- like to sword-like leaves. Cultivation of most species is easy. Nearly all can grow in the ground, and most, but the largest species, can live happily in pots. They are mainly warm season growers so provide some water during the spring through fall to get them to look their best.

Yucca is the largest and best known of these genera. Anyone traveling in the Mojave Desert has certainly seen Joshua Trees (Yucca brevifolia), one of the largest and most distinctive Yucca species. As close as the Mojave is, you don't even have to go that far to see a native Yucca. In our local hills grows Hesperoyucca whipplei (formerly Yucca whipplei), commonly called Spanish Bayonet because of the very sharp leaves or "Our Lord's Candle" due to the large (10 feet or more) white inflorescences produced in the spring can be seen from a mile or more away. While most Yucca species are better suited to being landscape plants due to their size, some do well as specimen plants in pots. Probably the most prized of these species is Yucca endlichiana, a small Mexican species with thick blue-green leaves and brown flowers (unique in the genus).

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 Uebelmannia - May 2014, September 2008, 2007, 2006

Uebelmannia does not produce a cephalium but is as much, if not more, highly prized than Coleocephalocereus. It is a small genus of globular to shortly columnar cacti with approximately three species, though some split up U. pectinifera into several different species. The genus is distinctive in having numerous spine covered ribs that give a very regular and pleated look to the plant. In addition most plants are various shades of purple to gray, giving even more beauty to the species. The most popular species is U. pectinifera and large, show quality, specimens can sell for hundreds of dollars. The biggest problem in growing nice big plants is their propensity to form marks and scars on the stems that detract from their appearance. A specimen sized plant without distracting marks is something to behold.

 . . . are from tropical regions and appreciate warmer temperatures. It is best to keep them at a minimum of 50 degrees in the winter, but they can be grown cooler (but never below freezing) if kept dry in the winter. Cool and wet makes them prone to rot. During the summer they appreciate more water than the average cactus.
-- Kyle Williams
Photo in Cactus Chronicle:
Uebelmannia pectinifera

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Uncarina - July 2007

Pterodiscus, Sesamothamnus, and Uncarina are all members of the Pedaliaceae or Sesame family. They are all still relatively uncommon succulents, in spite of the relative ease of growing many of them.

Uncarina, a Madagascan endemic is the most popular of the three genera. All of the species have underground, and sometimes aboveground swollen roots. There are about 15 species, with a few more likely to be discovered in the more isolated regions of Northern Madagascar. They are easy to grow, liking lots of water when in growth, but needing some protection from wet and cold in the winter.
--​ Tom Glavich May 2005
Photo in Cactus Chronicle:
​Uncarina grandieri entered in the 2003 Show by Naomi and Frank Bloss
Photo T. Nomer

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Varigates - November 2016, April 2015, January 2013, March 2012, October 2010, November 2008 & 2007

Variegation is the appearance of differently colored areas leaf or stem due to a partial loss of chlorophyll. This is usually due to genetic mutation, developmental abnormalities or certain viruses. People have also been able to induce variegation in plants through the use of radiation or treatment with certain chemicals. The scientific details of exactly how variegation arises in plants, and how it is maintained (or lost), are too complex to go into in depth here.

The pattern may be consistent and well organized (e.g. many Agave) or it may be randomly distributed (e.g. most variegated cacti). Plants with patchy or mosaic patterns of variegation are often the result of a cell mutation that is fairly random. In other words the plant may be prone to producing cells without chlorophyll sporadically, and when that cell appears it divides many times (just like normal cells). Some plants have fairly organized and consistent variegation patterns. That is quite often due to different meristem (i.e. mother) cells being responsible for forming different layers or parts of a leaf or stem. For example, if the meristem cells responsible for making the outer edges of a leaf have the variegation gene while meristem cells for the center of the leaf do not, you will get a consistent pattern of white edges and a green center.

Plants totally lacking in chlorophyll (achlorophyllus), such as the brightly colored grafted Gymnocalycium cultivars are technically not variegated, but are considered so for the purposes of cacti and succulent shows. Keep in mind, a plant is not variegated just because the leaves have colored areas. It must be partially lacking chlorophyll as well.

Variegated plants normally have white or yellow patches and streaks, but can also be colors including red, orange, brown, pink, and purple. Colors other than white are due to the presence of colored plant pigments such as anthocyanins and carotenoids.

Variegation is known throughout the plant kingdom, but is rarely seen in the wild. The reason variegated plants are common in horticulture is that people like the color and unusual nature of these plants. When a rare variegate appears in a batch of seedlings we are keen to grow it, propagate it and spread it around!

Variegated plants have a place in most gardens. The strange and colorful patterns bring unique visual interest to any collection. In cacti and succulent shows, variegates generally compete against other variegates to put them on an equal footing. The Intercity Show gives the following guideline for showing plants in the variegated category: "Plants with 30% or more variegation may only appear in such category except for variegation in Agave, Gasteria, Sansevieria."

In general, variegated plants grow slower and are smaller than non-variegates of the same species. They also tend to sunburn easily and most need more sun protection than a typical member of the species. Ironically, variegates also have less shade tolerance than their non-variegated counterparts. The reason for this is that chlorophyll "soaks up" the sunlight to make food. With less chlorophyll the plant needs more light to get the same amount of food, but at the same time the more delicate tissues are exposed to the light without any protection.  A good rule of thumb is simply not to grow variegates in extremely bright or dark situations. Otherwise, the care of a variegated plant is the same as for the normal form of the species. A large well grown variegate of any species is truly an achievement.

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