Dec.1 I, 1871] 



NATURE 



153 



THE MONOCOTYLEDON THE UNIVERSAL 



TYPE OF SEEDS* 



1 T must ba evident to those who heard my paper on " Adna- 

 tioM in Conifenu " at the Chicago meet ng of the Association 

 that the oKs-r\ations there detailed could scarcely be accounted 

 for, if the belief be true which is generally held by botanists, 

 that the leaf originates at the node from which it seems to spring. 

 It is not, however, an object with me to attack existing theories, 

 or establish new ones, but simply to present facts as I see them. 

 The origin of the leaf will no doubt prove a question which will 

 in time take care of itself. But this generalisation cannot be 

 avoided by the readers of that paper, that the whole plant is 

 originally a unity ; and that the subsequent formation of ele- 

 mentary organs, and their complete development, or absorption 

 into one another, is the result of varying phases of nutrition. 

 The leaves in Conifene were found to be free or united with the 

 stem in proportion to the vigour of the central axis. Following 

 up the subject, I now offer some facts which will show that all 

 seeds are primarily monocotyledonous ; and that division is a 

 subsequent act, depending on circumstances which do not exist at 

 the first commencement of the seed growth. 



It is well known that m some species of Coniferous plants the 

 number of cotyledons varies. I have noticed in addition to this 

 that whether the cotyledons are few or many, there is no increase 

 in the whole cotyledonous mass. In the Norway spruce, Abies 

 excflsa, there are sometimes as many as ten cotyledons, in others 

 only two. In the latter case they are broad and ovate, while in 

 the former they are narrow and hair-like ; in short, when in the 

 two cotyledoned state it is not possible to note any dillerence 

 between a seedling Norway spruce and a Chinese arbor vitx, 

 Biola oricntalis, except by the lighter shade of green. The two- 

 leaved condition is not common, but specimens of threes and 

 others I exhibited to Dr.«. Torrey and Gray at the Troy meeting. 

 Any one who will examine sprouting seeds of the Norway spruce 

 will agree to the proposition that the cotyledons are not original 

 and separate creations, but a divided unity. My next observa- 

 tions were on some acorns of Qnercus agrifolia, the division into 

 cotyledons were numerous and irregular. Cut across vertically, 

 some represented the letter C, others the letter N, and again, 

 with four cotyledons the letter M. Here again it was clear that 

 whatever the form and number of the cotyledons, there was no 

 increase of the original cotyledon mass. Examining sprouting 

 peach kernels, the variations in form and number were of the 

 most remarkable character. I need not repeat them in detail 

 here, as they are reported in the April and May " Proceedings of 

 the Academy of Natural .Sciences of Philadelphia." In addition 

 to the fsct of no increase in the whole cotyledon mass, it was 

 here clear that when the cotyledons were duplicated, the duplica- 

 tions at least were subsequent to the original ones. Still so far 

 nothing had been seen to indicate when the first pair of cotyle- 

 dons were formed. Qjiercus macrocarpa and Qiterciis paUistris 

 were silent to my questions. In a large number I found no 

 variations whatever. Each mass was divided smoothly and 

 exactly into two cotyledons. Querciis i-olnir, the English oak, 

 however, gave some curious evidence. Two germs under one 

 seed coat were numerous, and often three, and the cotyledons 

 took on a variety of forms. But there was never any more in- 

 crease in the cotyledonous mass than if but two lobes had been 

 formed, and there was no more rule in the division than there 

 would be in the sudden breakage of a piece of glass. A detailed 

 account of these will also be found in the "Proceedings of the 

 Academy of Natural Sciences of Philadelphia" for May. 

 QiiiTcus rubra, the American red oak, furnished the one link 

 wanting to connect the first division into lobes with the other 

 phenomena. All the acorns examined had three or four sutures 

 in the cotyledon mass, and extending all along the longitudinal 

 surface externally, without any reference to cotyledonal divisions. 

 These sutures extended sometimes but a line in depth, at others 

 almost to the centre of the mass, always accompanied by the 

 inner membrane, as is the case in ruminated seeds. The whole 

 mass was divided only in two parts in any that I examined of this 

 species, but the division was always in the direction of the sutures. 

 Hence each cotyledon was very irregular. Sometimes one-third 

 the mass only went to one while the other had two-thirds of the 

 whole mass. It was easier to burst in the weaker line of resist- 

 ance. But the interest lor us is to note that ordinarily the coty- 



* Abstract of a Paper read at the Indianopolis Meeting of the American 

 Association for the Advancement of Science, August 1871, reprinted from 

 the American Naturalist. By Thomas Meehan. 



ledonous inass was a unit — then the sutures or fissures were 

 formed, and ultimately the two divisions of the lobes followed in 

 their direction. The division was the last condition, not the 

 first. I kno.v how much we should guard against generalising 

 on a limited .supply of facts, but it requires an effort to believe 

 that oaks, pines, and peaches, as we have seen primordially' 

 monocotjledons, are in this respect different from other so-called 

 dicotyledonous plants ; and if we grant that all seeds are primarily 

 monocotyledonous, may we not ask why in any case they are 

 divided ? We have seen that there is no increase of mass in the 

 division, the same amount is furnished in one as in many. Would 

 it in any way injure the Indian corn to have its mass divided into 

 two lobes ? or would not the plantlet be as well provided for if 

 the acorn were in one solid mass ? Division would seem to be a 

 necessity occurring subsequent to organisation, and existing from 

 the position of the plumule alone. In monocotyledons, as we 

 know, the plumule is directed parallel to, or away from, the coty- 

 ledonous mas=, when, of course, on this theory, it remains an un- 

 divided mass. But in the dicotyledonous section, the plumule 

 is directed towards the apex of the mass ; and as we know in the 

 case of roots against stone walls, or mushrooms under paving- 

 stones, the disposition in the growing force of plants is to go right 

 forward, turning neither to the right nor the left ; so in this mass 

 of matter the development of the germ would make easy work of 

 the division ; and no doubt often at so early a stage as to give 

 the impression we have been under hitherto, that the division is 

 a primary and essential process. 



SCIENTIFIC SERIALS 



"Y-Ki. Monthly Microscopical Journal, No. 35, November 1871. 

 " On the Fprm and Use of the Facial Arches," by W. Parker, 

 F. R. S., is chiefly occupied by observations on embryo salmon. 

 " Another Hint on .Selecting and Mounting Diatoms," by Capt. 

 Fred. H. Lang, details the method employed by the author for 

 remouiuing diatoms, either previously badly mounted, or from 

 whicti it is desirable to select certain forms. — "The Monad's 

 Place in Nature," by Metcalfe Johnson, M.R.C.S.E., has for its 

 object to show a connection between the earlier forms called 

 Monads, and those higher and more complicated organisms at 

 present recognised under the name of Infusoria, Mucedinre, 

 Conferva?, Ctscillatoriae, &c. The conclusions deduced from 

 some of the experiments are that the author looks upon Monas 

 in its earliest forms to be the starting point whence several pro- 

 ducts may result, and among the number are Infusoria, Mucedinao, 

 Englen3=, Oscillatori.-e. He is induced to believe that the Pm- 

 point Monad, when developed under absence of light and only a 

 limited qu.antity of air, gives rise to the class of plants known as 

 MucedinK. Again, he maintains that during the watching of the 

 liquids under experiment the Monads presented various forms, 

 evidently transitional, from the round Pin-head Monad to oval 

 young Paramrecia, until we come to sufficient size to give it a 

 name such as Kolpoda Cucullus, &c. — "Infusorial Circuit of 

 Generations," by Theod. C. Hilgard, deals with a similar subject, 

 but in a very different style. It is often very difficult to gather 

 the author's meaning from language such as the following : — 

 "And from each little dot in these ' clouds of life' a separate 

 vorticella can be seen to develop ! It is here, indeed, at this 

 first visible advent or exordium of animate life, and the resurrec- 

 tion of millions of germs through the spontaneous dissolution of 

 a single one, that the last nubecular microscopic perceptions 

 closely resemble the last nebular telescopic as welt as the theoretic 

 ones of Laplace's cosmogony." The concluding portion of this 

 paper, which is reprinted from Sillinian's Journal, appears in 

 the succeeding number, and is interesting as a contribution to the 

 "curiosities of scientific literature." 



The Monthly Microscopical "Journal, No. 36, December 1871. 

 — " Notes of Prof James Clark's Flagellate Infusoria, with 

 Descriptions of New Species," by W. .Saville Kent, F.Z.S. An 

 entirely technical paper, consisting of the diagnostic characters 

 of new species, with those of previously-described ones amended. 

 Eleven forms are figured and described, all of which were found 

 in fresh water at Stoke Newington.— •' On Bog Mosses," by R. 

 Braithw.-iite, M.D., F.L.S., Part II., is occupied chiefly with the 

 anatomy of the leaf and development of the plant.— " On the 

 Conjugation of -Amceba," 'oy J. G. Tatem, is a note serving to 

 strengthen the supposition previously advanced by this author, 

 " that these large Amceba? so frequently met with in the autumn 

 months are actually the incorporation of two individuals in a 



