. Contributions from the Osborn Botanical Laboratory. Plants. 290 EVANS. Marginal gemmae occur abundantly on some of the plants collected iby Neger but are apparently absent from all the other specimens. The gemmiparous branches are essentially like the others and present no evidence of limitation in growth. The gemmae are usually scattered, although a crowded series is sometimes to be observed, and the mother-cells of the gemmae arise directly from the marginal cells, just as in (4, p. 277). At the time of separation the gemmae vary considerably in size, average examples measuring p
. Contributions from the Osborn Botanical Laboratory. Plants. 290 EVANS. Marginal gemmae occur abundantly on some of the plants collected iby Neger but are apparently absent from all the other specimens. The gemmiparous branches are essentially like the others and present no evidence of limitation in growth. The gemmae are usually scattered, although a crowded series is sometimes to be observed, and the mother-cells of the gemmae arise directly from the marginal cells, just as in (4, p. 277). At the time of separation the gemmae vary considerably in size, average examples measuring perhaps mm. in length and mm. in width. Most of them are oblong in form, six to eight cells across, and show an indistinct stalk and a single apical cell. Crowded rudiments of marginal hairs, slightly displaced to one surface, are usually present and not infrequently show a paired arrangement. Otherwise the gem- mae are scarcely differentiated. In germination (Fig. 4, B-D) the young plant is at first noth- ing more than a slightly narrower extension of the gemma, although in one somewhat older "example a rudimentary costa was present with a wing three cells wide on each side. No late stages of germination have been observed. The list of specimens cited brings out the fact that M. divari- tiG. 4. Metzgeria divaricata Evans. ,, p •, cata, apparently on account ot its A. Marginal portion of a thallus- variabilitv, has been confused wing, ventral view, X 50. B-D. Ger- .,, ,, .i • fU( minating gemmae, X 100. A was drawn Wlth three other species of Mdz- from the type material; B-D, from a geria. In the structure of the specimen collected in Chile by Neger, costa with its two rows of dorsal and four rows of ventral cortical cells it agrees with M. conjtigata and M. /areata; in having ventral hairs, sometimes produced in considerable abundance, it agrees with M. eorralcnsis. It is, however, amply distinct from all three species. It differs from M. conjvgata in
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