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Pachyphytum oviferum is a member of the Crassulaceae family. These plants’ are commonly known as the succulents. The genus Pachypytum includes the species Pachyphytum oviferum. Pachyphytum oviferum is better known by its common name the “moonstone” plant. It retains this name due to its beautiful firm and stone like shaped leaves. Pachyphytum, in Latin, means “massive plant” and it will soon be apparent why.In 1841 the genus was first discovered by Klotzsch in Mexico. The first to be noted was P. bracteosum. The evolution of Pachyphytum is most likely associated with Echeveria. The discovery of this genus led to much discussion and disagreement among botanists, due to their strange characteristics. These oddities led many botanists to place the plant in different genus, though later it was proved that this plant belonged in its current genus. There are now over 20 known species and all are native only to Mexico These beautiful little plants grow on very steep cliffs with elevations easily reaching 600- 2500 meters. Because these habitats are mostly inaccessible, the locations of these plants are still not definite and sometimes are unknown all together. Information provided by Poellnitz in 1937 has only allowed the exact location of three species. Not much is known of these incredible little plants in the world of botany but one thing is sure, they are very unique and are worth every bit of trouble in finding them. The leaves have a purple hue to them, add this to their smooth silvery appearance is truly something to behold. The leaves may be rounded to elliptical. Hydathodes, secretory tissue, are commonly present in the leaves. These allow water to be secreted through holes in the epidermis. Pachyphytum oviferum is Xerophytic, meaning it has adapted to living in arid and hot environments. The blade of the leaf is entire. Pachyphytum oviferum is a perennial, with a basal aggregation of leaves. The leaves appear to be whorled, sessile, and plane (defined typically as a “rosette”). No sheathing is present. Pachyphytum oviferum is a non-deciduous plant. The leaf base can best be described as peltate, having the stalk or support attached to the lower surface at a distance from the margin. It is difficult to observe the veins of this plant but they may be either one-veined, or pinnately veined. Within the veins may be transfer phloem cells, although they may be absent. Also, the leaves do not have a continuous basal meristem .The stem is succulent, lateral, and is usually about half an inch thick. A cork cambium is present within the stem. Cortical bundles are visible although there is no internal phloem. There are secondary thickenings that will develop from the cambial ring. The plant engages in pollination as its primary mode of reproduction. The flowering of Pachyphytum oviferum is one of the most beautiful sights. The flowers develop on a large droopy pink stalk between bracts ref>Watson, 2008. The flowers are tubular and are surrounded by sepals. The outside of the flower is typically a light green to silver. The inside is a striking deep reddish orange surrounded by a light pink. The flowers are typically aggregated in what is referred to as inflorescences, which is the arrangement of the flowers on an axis. Upon the inner side of each petal is a pair of scales which close off the lower corolla, the part which surrounds the organs of fructification, with its nectar ref>Baldwin, 2007. Smith, 2008. Dortort, 2007. The biochemistry of Pachyphytum oviferum is not all that surprising. Alkaloids, Proanthocyanidins, and Flavonols are typically present. Because of their habitats, mostly hot and arid, these little plants have developed a unique strategy to overcome water loss. It is called Crassulacean acid metabolism or CAM. These plants use both the C4 pathway as well as the Calvin cycle. They have the ability to fix carbon dioxide in the dark with the assistance of PEP carboxylase within the cytosol. The product of malate is stored as malic acid within a vacuole until the next light period. Therefore, a main characteristic is the presence of large vacuoles as well as chloroplasts. These plants rely on nighttime accumulation of carbon dioxide because their stomata close during the day to prevent water loss. In 1973 chromosomes were identified in selected species of Pachyphytum. Thirty-one to thirty-three chromosomes are present, and can be referred to as diploid. In some five species studied only diploid forms were present, yet others were found to be tetraploids. Research showed that there are levels between two and five of ploidy. Research conducted on Pachyphytum, the six known species at the time, yielded diploids and tetraploids with x=33. Of these were Pachyphytum oviferum and it too was found to be diploid (x=33)ref>Uhl, 1973. All these unique features have led to an increased desire to cultivate these plants. The whole genus Pachyphytum is widely cultivated and widely available. Pachyphytum oviferum is much harder to find which is ironic due to the fact that it is the most cultivated. After planting my own succulents I saught advice on how to cultivate these little plants. I recieved advice from Laurie Kasperek of the EW Heier Teaching and Research Greenhouse at Binghamton Universty. Here are her reccomendations. Out of the known species, Pachypytum oviferum requires more heat than the other species. This makes growing it outdoors difficult because it is very sensitive to frost as well. Some tips if you are considering growing these “moonstones”; keep it away from windows because of its temperature sensitivity, in summer month’s water weekly until fall when it is dormant and requires only biweekly watering. Food is only necessary twice yearly. In the winter the temperature typically tolerated is a low of 6 degrees C (or 43 degrees F). Start looking for your tiny blossoms in the days between March and April. To propagate cuttings are recommended as well as collection of seeds. ENJOY!

Works Cited

Baldwin, Debra Lee. "Designing with succulents". pg 126, 156-157. 3rd printing 2008 Timber press 2007

Dortort, Fred. "Amethysts, Pearls and other things". Succulent of the month. University of California Botanical Garden at Berkeley. 2007. http://botanicalgarden.berkeley.edu/SOM/SOM-grapto.shtml

Hewitt, Terry. "The complete book of CACTI and succulents: the definitive practical guide to cultivation, propigation and display". DK publishing INC, 1993. London, New York, Munich, Melbourne and Delhi.

Low, James E. "Genus Pachyphytum". International Crassulaceae Network. 22, December 2007. http://www.crassulaceae.net/index.php?option=com_content&view=article&id=157:genus-pachyphytum-uk&Itemid=27

Raven, Peter. Evert, Ray F. Eichhorn, Susan E. "Biology of Plants". W.H Freeman and Company Publishers. Seventh Edition. 2005

Smith, Gideon. Wyk, Ben Erik-van. "The Garden succulents Primer: How to identify and grow the most popular drought tolerant plants".pg 122. Timber Press Portland, London. 2008

Watson, L. Dallwitz, M.J.1992 onwards. "The Families of Flowering Plants: descriptions, illustrations,identification, and information retrieval". 30, April 2009. http://delta-intkey.com’.

Uhl, Charles H. Mora, Reid. "The Chromosomes of Pachyphytum (Crassulaceae)".pg 648,651. Division of Biological Sciences, Cornell University, Ithica New York and Natural History Museum, San Diego, California.1973.