A morphological study of some members of the genus Pallavicinia . Pallavicina radiculosa. A. Male plant, x 3. B. Cross-section of young conducting tissue, very highly magnified. C. Midrib of the thallus, showing the position of the antheridia. D. Young; E, older rhizoids. METHODS 15 shoot, and finally almost completely disappear, so that the oldest part ofthe shoot is almost perfectly cylindrical. The surface of the wings issmooth and the margin undulate, but not developing lobes or teeth, in thisrespect differing from P. Zollingeri. The ventral surface of the midrib is completely covered by s
A morphological study of some members of the genus Pallavicinia . Pallavicina radiculosa. A. Male plant, x 3. B. Cross-section of young conducting tissue, very highly magnified. C. Midrib of the thallus, showing the position of the antheridia. D. Young; E, older rhizoids. METHODS 15 shoot, and finally almost completely disappear, so that the oldest part ofthe shoot is almost perfectly cylindrical. The surface of the wings issmooth and the margin undulate, but not developing lobes or teeth, in thisrespect differing from P. Zollingeri. The ventral surface of the midrib is completely covered by shortpapillate hairs, like the true rhizoids, outgrowths of single superficial papillae become longer in the older parts of the thallus, andgradually give place to the long, dark purple-red rhizoids, which in thebasal region form a dense mass. These conspicuous rhizoids (Fig. 7,D, E) are composed of a single cell, but develop a number of shortbranches at the apex. As in P. Zollingeri ventral, apparently adven-titious branches are developed which much
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Keywords: ., bookauthorcampbelldouglashought, bookcentury1900, bookdecade1910
