SPORE DEVELOPMENT AND MORRHOLOC.Y 



11 



by treatment with 10 percent KOH, and 

 subsequent decantation. Some weathered 

 coals require only the latter phases of the 

 treatment, the oxidation phase having been 

 completed by nature. 



Spores are isolated from clays, shales, and 

 sandstones with HCL and HF treatments. 

 Other spores may be picked from bedding 

 planes of a sedimentary rock and merely 

 cleaned with dilute HF. A summary of 

 the various methods applicable to the iso- 

 lation of organic matter from all kinds of 

 rocks, in all degrees of induration, has been 

 published recently by Sittler (1955). 



The 65-mesh (the figure indicates the 

 number of meshes to the inch) Tyler screen 

 has mesh openings of about 210 /a. The 

 residue passing through the 65-mesh screen 

 generally is stained in safranin Y and 

 mounted under a cover slip with glycerine, 

 diaphane, or balsam, and examined for 

 small spore content. (A discussion of vari- 

 ous mounting media and their advantages 

 and disadvantages is given by Christensen 

 [1954].) The coarse, plus 65-mesh residue 

 may contain sporangial masses of small 

 spores, megaspores, or large spores, spores 

 rather small for "large" spores (200 to 

 400 fi), cuticle, seed membranes, waxy 

 blebs, resin rodlets, fusinized wood and 

 vascular fragments, and incompletely mac- 

 erated coal fragments. Additional sieves 

 may be used to separate the coarse residue 

 into various size fractions. The coarse resi- 

 dues commonly are stored in alcohol and 

 glycerine in wax-sealed bottles. 



All coarse residues used in this study- 

 were examined immersed in water in a petri 

 dish under a binocular microscope at mag- 

 nifications of 6X to 36 X. The large spores, 

 some sporangial masses, cuticles, vascular 

 tissues, and seed membranes were picked 

 from the dish with a flattened needle. Sub- 

 sequently the specimens were mounted dry 

 on cardboard mounts or, as with the ma- 

 jority of specimens, passed through alcohol 

 to xylol and mounted in balsam on slides, 

 the most permanent media for megaspore 

 mounts. More than 1,000 balsam and dry 

 mounts were examined. 



Descriptions and measurements are based 

 largely on the examination of specimens 

 mounted in balsam because the fine orna- 

 mentation details are adequately observed 

 only by transmitted light. This phase of 

 the work was done on a research micro- 

 scope at magnifications of 150X to 500 X. 

 Photographs were taken on fine-grained 

 film with both transmitted and reflected 

 light. A red filter was used in photograph- 

 ing some of the highly ornamented thick- 

 walled megaspores in order to show details 

 of the spore body and its ornamentation. 



SPORE DEVELOPMENT AND 

 MORPHOLOGY 



The spores described and discussed in 

 this report were largely, perhaps entirely, 

 derived from vascular plants, the Tracheo- 

 phyta. Many of the plants were large and 

 treelike and are referred to as arborescent. 

 Others grew close to the ground and are 

 called herbaceous. All vascular plants pro- 

 duce spores of some kind and have an alter- 

 nation of sporophyte and gametophyte gen- 

 eration during their life cycles. 



The mature plants, part of the sporo- 

 phyte generation, produce spore mother 

 cells, each of which produces four unicellu- 

 lar spores of the gametophyte generation. 

 Some vascular plants are homosporous, pro- 

 ducing spores that germinate into multi- 

 cellular gametophytes, which in turn pro- 

 duce both male and female gametes. Other 

 plants are heterosporous and bear: 1) mega- 

 spores that germinate into multicellular fe- 

 male gametophytes that produce female 

 gametes and 2) microspores that germinate 

 into multicellular male gametophytes that 

 produce only male gametes. The union of 

 female and male gametes initiates the sporo- 

 phyte generation of the life cycle. 



Most spores are enclosed within a pro- 

 tective coat that is resistant to chemical and 

 physical attack. Because of this, the spore 

 coats or exines, referred to generally as 

 spores throughout this paper, commonly 

 are well preserved in coals and many kinds 

 of sediments. The gametophyte inside the 

 spore coat is preserved only under excep- 

 tional conditions. 



