Bryology for the High School * C. Grant Roehrick,Biology Department,Pasadena Senior High School, Pasadena,Texas The study of mosses and liverwortshas been relegated to a very minor role in much of the "new biology." That these organismsmay offer unusual fields of investigation is the author's contention. Downloaded from http://online.ucpress.edu/abt/article-pdf/26/2/124/21453/4440569.pdf by guest on 30 September 2021 Introduction Difference Between a Moss and a Liverwort The bryophytes are among the most neglected organisms in the plant kingdom. In general, it can be said that the difference This is probably due to the lack of pro- between a moss and a liverwort is mor- fessional bryologists. Actually the mosses phological. This difference is obvious when and liverworts are extremely important and comparing a moss with a thallus liverwort. should receive far more attention because However, not all liverworts are the thallus of their evolutionary implications. You can type; some are leafy and resemble a moss place the mosses directly between the non- nost remarkably. One characteristic that vascular and vascular plants as a living repre- would distinguish a moss from a leafy liver- sentative of the old world flora. The mosses, wort is the presence of a nerve (midrib); of course, experience an alternation of their present only in the leaf of the moss. This is generations (sporophyte and gametophyte), not totally dependable, however, because but equally significant are their asexual re- not all mosses have a nerve present in their production processes with gemmae and "leaves."'' As far as sterile (not fruiting) paraphyllia. material is concerned, diagnostically you can observe the cellular structure of the phyl- Ecologically, the mosses and liverworts lbids called areolation, and also the arrange- have world-wide distribution that can indi- ment of the phylloids on the "stem."2 The cate the a characteristics of particular cells of the liverwort leaf are usually cuboid, area. geographical These cryptogams are whereas in the moss, cellular elongation is quite adaptable in their environmental situa- most common. Furthermore, leaf arrange- tions, and can vary in their life cycle, size, ment in the liverwort is three-ranked with to color, and microclimate according where two of the leaves usually opposite, while the they are found. From the tundra to the third leaf is small and underneath the tropical rain forests and to the desert, the larger ones. Leaf arrangement in the mosses mosses are generally specific for each of varies from a two-ranked appearance to an these areas. There are mosses that typically appressed sheathing characteristic. accumulate in greenhouses that are normally not found in other habitats. Species varia- Reproductively the mosses produce a con- tions can change from niche to niche, but the spicuous capsule usually borne at the ter- genera can often be world-wide. To illus- minal end of the seta, with or without a trate the varying ecological niche of the calyptra, and always showing a cap or lid. If mosses, they can be found growing on trees, a capsule is produced in the liverwort, it will rocks, loose sand, forest floor, open fields, split lengthwise forming four valves for the and completely submerged in fresh water release of the spores. streams. In summary, then, the bryophytes can be divided into three groups: (1) mosses, (2) This, then, should indicate that the bryophytes can be interesting and chal- 'In bryology, the term "phylloid" is more common- lenging if you would take the time to notice ly used in place of leaf. them, to collect them, and to study them. 2The term "cauloid" is often substituted for stem. 124 BRYOLOGYFOR THEHIGH SCHOOL 125 leafy liverworts, and (3) thallus liverworts. within 3 inches of the top, fold each side in For identificaton of the bryophytes, a closer 1 !/2 inch, finally fold the top down until look at all of the diagnostic characters in the you have an envelope with dimensions of laboratory is imperative, and only after this 5?V2"x 4". The identificationlabel can then close examination can you begin to apply be attachedto this top flap. This label should a taxonomic key to the specimen. include: genus and species, date collected, brief description of the habitat, location of Field Identification collection station, your name (or collector's Equipped with a lOx triplet hand lens, name), and herbariumnumber (optional). genera identification in the field can come to These packets can then be stored alpha- you only after you have repeatedly recog- betically in shoe boxes. nized the outstanding characteristics of the Before placing the specimenin the packet, genera. This of course takes practice, time, all trash and as much dirt as possible should Downloaded from http://online.ucpress.edu/abt/article-pdf/26/2/124/21453/4440569.pdf by guest on 30 September 2021 and patience. If you are conscientious and be removed from the sample. You should return to the field frequently, it should take preserveonly clean specimens;a dirty speci- a relative short time before you become men is not worth saving. It is not necessary intimately familiar with the local flora. to press the moss or liverwort; if you do, use only light weights. With your moss or Collection and Preservation liverwort placed in the packet and properly An army surplus bag such as a gas mask labeled, it will remain unharmed for an bag, a lOx triplet hand lens, a few dozen undeterminednumber of years. If years later small paper bags-size No. 2, and a small you wish to re-examine or compare this field notebook is all the equipment a specimen with another, just simply soak in bryologist needs for field work. The rest water. The mosses will turn green, unfold, is not easy! You have to look for the and appear much as they did the day you bryophyte. Many times they are in the collected it. open, forming a carpet; other times they You will find that after a few trips to the will be found in crevasses of rocks and on field, and many hours in the lab you will be the trunks of trees. If a creek or other water rewarded with a good beginning of a areas are present, then you must look along bryological herbarium. In a year or two, the banks and in the stream itself. Look on you possibly will have a valuable repre- rocks, around rocks, and under rocks. The sentation of the local flora. bryophytes grow everywhere. When you collect, be sure to obtain as Laboratory much of the growth as practical-at least Many useful experiments can be at- a handful. If it is fruiting, be sure to include tempted in the laboratory; however, with this in the specimen. If you can make a many of these experiments, a considerable field identification, write this name on the amount of technique is required. After paper bag, place the moss in the bag and several attempts at these more precise ex- record the location, date, and niche particu- periments, the problems that previously lars either on the bag or in your field note- arose seem to iron themselvesout. book. It is good to keep a record of some of the Upon returning to the lab, confirm your outstandingmicrocharacteristics of the bryo- identification by running the specimen phytes. This can be accomplishedby making through a taxonomic key. Here, I would like slides that will be relatively permanent. to recommend: H. S. Conard, How to Know Perhaps the best medium for both pre- the Mosses and Liverworts, W. C. Brown serving and mounting is a "gum choral" Co.: Dubuque, Iowa, 1956. This book is a mountingmedium. This preparationis made good key, easily understood, and fairly well as follows: illustrated. Distilled water 100 ml To preserve and store your collection, small Gum arabic 40 g packets made with a good grade of rag con- Glycerine 20 ml tent typing paper 8?/2"'x 11" is used. To Chloral hydrate 50 g make these packets, fold the bottom up to Dissolve the gum arabic in cold distilled water, 126 THEAMERICAN BIOLOGY TEACHER add the glycerine and chloral hydrate. Heat of the bryophytes. gently in a water bath until all solutes are com- pletely dissolved. Filter while still hot. Conclusion A more simple process and still quite Whether as a hobby, a profession,a thesis permanent is to place the tissue on a slide problem, or a subject to teach, the bryo- with a drop of water. Cover with a glass phytes should be taken more seriously. If a cover slip. Gently heat over an alcohol lamp sincere effort is put forth to study the until the water begins to steam;this will re- ecology, morphology, taxonomy, or what move air bubbles.After this has dried, place have you, you will find that the mosses can a drop of concentrated glycerine near the develop a fascination that will send you cover slip so that the glycerine will diffuse to the field again and again. Not just the between the slide and the cover slip. Allow peculiaritiesof these plants alone can con- for to dry thoroughly forty-eight to seventy- vince you upon delving into the subject Downloaded from http://online.ucpress.edu/abt/article-pdf/26/2/124/21453/4440569.pdf by guest on 30 September 2021 two hours. deeper, but with repeated contact with the Still a third method (not recommended)is bryophytes you will find them filling a gap to use a drop of Canadianbalsam cement, in your biological knowledge. then cover with a glass cover slip. It is an excellent field to get into pro- The more common materialyou will want fessionally.