Development of Pluteus admirabilis and Tubaria furfuracea
Leva B. Walker
Vol. 68, No. 1 (Jul., 1919), pp. 1-21
Published by: University of Chicago Press
Stable URL: http://www.jstor.org/stable/2469183
Page Count: 26
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Pluteus Admirabilis 1. No entirely undifferentiated primordium of a basidiocarp was obtained. The earliest stage secured showed a differentiation into primordia of stipe, pileus, and hymenophore. 2. All parts of the young basidiocarps are covered with free ends of hyphae which lie more or less parallel to each other. The primordium of the hymenophore is distinguishable by the smaller cells composing it, with denser protoplasmic contents. It develops at the angle of junction between pileus and stipe. This soon becomes a definite level palisade layer. It is entirely exogenous in origin. 3. There is a strong epinastic development in the margin of the pileus and it becomes so strongly incurved that the filaments on its margin intermingle with those on the surface of the stipe. This occurs while the hymenophore is still in a level palisade condition. 4. The gills originate as downward growing folds which develop centrifugally, the first folding taking place at the point where the fundament of the hymenophore was first distinguishable over the angle of stipe and pileus. 5. The secondary gills originate in the same manner as the primary gills but at varying distances from the stipe. Their development is centrifugal. 6. The primary gills during their early development are attached to the stem and only become free during the final expansion of the fruit body. 7. The cystidia are distinguishable as soon as the gill salients appear. They appear as larger cells with scanty protoplasmic content, while the smaller cells of the hymenial layer are densely filled with protoplasm. 8. The cystidia are formed terminally upon filaments similar to, but usually larger than, those that bear the smaller cells of the hymenial layer. In younger stages the filaments bearing cystidia are little if at all branched, but in older fruit bodies they become more branched. The filaments bearing basidia and paraphyses branch profusely very early in their development. 9. The surface of the pileus is covered with cells that are similar to the cystidia. 10. The trama in the young gills is composed of a few slender filaments which lie more or less parallel to each other. During expansion large elongated cells developing from the subhymenium grow inward and downward, giving a very unusual appearance to the trama. These cells probably represent internal cystidia. The cells of the original trama become much enlarged also. 11. The cells in all parts of the young basidiocarps are constantly binucleate.