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On Cuecuta (Bronopii/" 



By Henrietta E. Hooker, Ph.D. 

 Plate 1 6. 



FOR a parasite that is parasitic from its heart and with all its 

 heart, after having tried an honest life, there is perhaps no 

 better example than Dodder, which in our region (S. 

 Hadley, Mass.) is Cuscuta Gronovii. We find it in abundance 

 in autumn, early and late, twining its orange-coloured stems about 

 grass, solidago, alder, and the like, with a glory of white, bell- 

 shaped flowers, in cymose clusters, appearing as lateral buds in 

 the axils of bracts. 



In preparing for the study of Cuscuta, fresh plants were placed 

 in alcohol, some were dried — as gathered on the host — and seeds 

 were sowed in pots. From the first, imbedded in celloidin, slides 

 were prepared. The dried specimens yielded knowledge of 

 external parts and abundance of seeds, which were valuable in 

 ways that will appear later. The seeds are exalbuminous, of 

 comparatively large size, with a conspicuous hilum and hard testa ; 

 but the latter yielded readily to soaking in dilute potash, and 

 careful dissecting removed the two coats and freed the coiled, 

 snake-like embryo (Fig. i). The root end of the embryo lies 

 outermost, and is slightly enlarged, more noticeably so after ger- 

 mination, when it evidently remains, for some time, a store-house 

 of nourishment. 



The time required for germination was found to vary much. 

 Some of the autumn-gathered seeds germinated in three days, 

 after a few days' soaking ; others, obtained from alder twigs out 

 of doors, in February, and sowed dry, were three weeks in 

 showing signs of life. The end of the stem which first emerged 

 from the seed-coats was very soon covered with numerous short 

 rhizoids, and careful observations failed to discover any trace of a 

 root-cap. Figs. 2 and 3 illustrate seedHng dodders. The tip 

 produces, even at a very early stage, the rhizoids mentioned. 

 Comparing Fig. 3 with Fig. i, it will be seen that the root-hairs 

 must have grown very rapidly, none being on the embryo, just 



* From the Botanical Gazette, 



