282 MORPHOLOGY OF ANGIOSPERMS 



of the cotyledons are united throughout their length, showing 

 two opposed bundles, as in the cotyledon of Anemarrliena. 

 Attention should be called to similar cotyledonary tubes in 

 Dicotyledons, and since nearly all of these are geophilous plants 

 Miss Sargant 21 has inferred that the fused condition of the 

 cotyledons in the monocotyledons has arisen in connection with 

 the geophilous habit. We herewith reproduce Miss Sargant's 

 list of dicotyledonous seedlings with a well-marked cotyledonary 

 tube. 



Anemone coronaria, A. alpina, A. blanda, A. narcissiflora, A. rupi- 

 cola, Ranunculus parnassifolius, Trollius Ledebouri, Erianthis hiema- 

 lis, Delphinium nudicaule, D. hybridum and vars., Aconitum Anthora, 

 Leontice vesicaria, L. altaica, Podophyllum peltatum, P. Emodi, Car- 

 damine spp., Oxalis spp., Rhizophora Mangle, R. conjugata, Megar- 

 rhiza californica, Smyrnium perfoliatum, S. rotundifolium, S. Olusa- 

 trum, Bunium luteum, Chaerophyllum bulbosum, Prangos ferulacea, 

 Serratula radiata, Dodecatheon Meadia, Polygonum Bistorta, P. sphae- 

 rostachyum, and Rheum Moorcroftianum. 



Holm 7 has also studied the two completely united cotyledons 

 of Podopliyllum, which suggested to him the possibility that 

 the " pair " may be regarded as a single cotyledon. In her 

 study of the " monocotyledonous Dicotyledons/' Miss Sargant 21 

 claims that the so-called single cotyledon is a fusion of two 

 cotyledons, special reference being made to the well-known case 

 of Ranunculus Ficaria. It may be noted also that in 1896 

 Delpino 2 urged the origin of the monocotyledonous phylum 

 from Dicotyledons through Butomus. Recently Hallier, 20 bas- 

 ing his phylogeny upon sporophylls and foliage leaves (" tro- 

 phophylls"), has urged the origin of Monocotyledons from 

 Dicotyledons, claiming that they have arisen from the region 

 of the Ceratophyllaceae and Ranunculaceae. 



There can be no question that among the Xymphaeaceae, 

 Ranunculaceae, and Berberidaceae there occur anatomical struc- 

 tures very suggestive of Monocotyledons, as Campbell 15 has 

 recently pointed out, but that this proves the origin of Mono- 

 cotyledons from Dicotyledons rather than the reverse is not 

 evident. Even the evidence derived from cotyledons has been 

 taken by Lyon 14 as indicating that the dicotyledonous condi- 

 tion has been derived from the gradual splitting of the single 

 cotyledon of Monocotyledons. If the view of the phylogeny of 



