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introductions that may come in, and decide whether you already have it or not.
On a separate subject, that of making collections of the plants as herbarium material. I would be very pleased to have collections from the Virgin Islands to compare with the material I have from Jamaica, Cuba and Trinidad. However, the process of making herbarium samples of cassava is quite a bit more complicated than for wild plant material, if you follow the same methods I have used, and evolved, over the years. Frankly, an ordinary herbarium specimen, with the usual type of specimen is not worth the paper it is attached to. You can decide whether it is worth it to you to follow my procedure, but I am sure that you will see the merit of the procedure, once you've been working with cassava variation. Many of the plants will not produce flowers, except under adverse conditions, and you can't wait until the flowers are produced, so you have to work the vegetative plants alone, sometimes. At any rate, I always include in my herbarium specimen a vegetative stem apex (about 6 inches long), with the young leaves attached, and preferably one leaf a bit more mature. Then, one mature vegetative leaf from farther down the stem, cutting off a section of the stem with the leaf for the specimen. Here, I always make a count of the numbers of lobes per leaf, and if there be variation on the same plant, but with one predominant number, I pick the most common representative. Then I make a long section of mature stem, about 1 foot long. I always take a long section of the root, cutting away both sides and leaving about 1/2 inch thick section of the most "typical" root, from point of attachment to the opposite end, through the center of the root. I usually tie the root section to the stem section to prevent the root from breaking, and then tag them with the same field number as the above-ground parts (the leaf, and the flower and fruit, if the latter are present). I have found it necessary to immerse the root and stem section in about 5 -10 percent formaldehyde for a couple of hours to prevent mold growth and to hasten drying.
You can see from the enclosed herbarium label the type of information I collect in the field. For color, I use the Mickerson Color Fan, put out by the Am. Hort. Council. This color fan sells for $6.00, and is really worth the money. This is the best way I know to standardize color designations though I will admit that any color comparison is liable to all sorts of interpretations. However, there may be a bit more objectivity in this technique.
I always made a black and white photograph of each cultivar that I make a specimen of--against a three-meter high backboard divided into thirds, and with a portion of the board marked off in subdivisions of meters 0.5 m., 0.1 m., etc. This is to reinforce the other information, and is quite helpful when examining the herbarium specimen. This may be eliminated if you are willing to record height, and branching pattern in detail as part of your field notes. I have found the photograph very useful, however, and invariably make an exposure to accompany any and all specimens of my own. Enclosed is a photo of one of my earlier photo-backboards. I modified this later, but don't have a spare photo to send you.
The herbarium specimen is also the document I used to keep information together concerning whatever analyses are made of the roots, or the leaves. This is, I find, an excellent way to keep your knowledge current. For example, I recently had analyses of 20 cultivars made for the amino acid content of the foliage. This work was done in hopes that the foliage may become significant as a protein-producing adjunct in tropical diets. The analysis of each of the cultivars is recorded on the specimen, as well as being the subject of paper we are at work on at the moment. I may place one reprint of this paper with the specimens, when the paper appears.
I would like to record on the specimens the time of maturation, cultural requirements where these are known, etc., but have never been able to work at a station long enough to get this type of agronomic, or horticultural, information. That's one reason why I hoped we might get together for a continuing project there in the Virgin Islands--under the aegis of the USDA, it might be possible to hold a set of experiments together long enough to gather yield data, fertilizer requirements, disease susceptibility, etc., etc.
