14S REPORT— 1861. 



for the growinp: out of the rootlet, whose colls are ormed in the upper part. Many 

 of the cells nm into sliort hollow hairs, which, like the cells, have a very thin mem- 

 brane. The fluid taken in by the rootlet after a time destroys the outer layer of cells, 

 and the second layer conies into play; but the constant production of new cells in the 

 interior causes the rootlet to increase in size. Passing from cell to cell, the fluid 

 becomes changed into sap ; but the sap difters in every cell, and each cell, around 

 one well filled, gets out of it a different kind of food. The author contends that it 

 is not possible to get into a plant anything that is a poison to it. The result will 

 be, if poisonous matter is present, that the outer layer of cells will be destroyed, 

 succeeding layers presenting themselves, and also being destroyed, so long as the 

 poison exists around. If the poison gets into the outer cells before they are wholly 

 destroyed, it will not be talcen up so readily as nutritious liquid ; and in any case, 

 after ti'aversing a few rows of cells, all poison will be retained, while other portions 

 of the plant will remain uninjured. 



On the Relation between Pinnate and Palmate Leaves. Bij Maswe'll T. Mas- 

 ters, F.L.S., Lecturer on Botany, St. Oeorge^s Hospital, London. 



It is now generally admitted that the difl'erent fonns of leaves, in spite of their 

 immense number, may be reduced to one or two primary fonns, the deviations fi-oni 

 which are to be accoimted for by such circumstances as increased growth in one 

 direction as contrasted with that in another, arrest of development at particular 

 places, and the like. The ensuing remarks merely tend to confirm this opinion and 

 to add additional illustrations of it. 



There are many cu'cmnstances leading to the inference that true palmate leaves, 

 as well as those that are pabnately divided, are but modifications of true pinnate 

 leaves, or of pinuately divided ones ; that in the palmate leaf gi-owth takes place 

 more in a lateral direction than in a vertical one, whereas growth in length at the 

 expense of gi'owth in breadth is the guiding principle in pinnate leaves ; the one, 

 so to speak, is a broad leaf, the other a long leaf Again, in the palmate leaf there 

 is an arrest of development in the portions of the loaf intermediate between the lobes 

 or leaflets according as the leaf is simple or compound, and thus the palmate leaf 

 may be regarded as a contracted pinnate leaf. In support of these assertions the 

 writer may refer to the fact, that pinnate and palmate leaves exist in the same 

 genera ; compare the leaves of Acer pscu do-plat ami ^, for instance, with those oi Acer 

 Kc'ffumlo, the leaves of liiibits micrantJnts with those of liiihus fruticosui; indeed the 

 circumstance is of such common occmTcnco that it is imnecessary to give further 

 illustrations of it. Of pi-eater value for our present purpose are those instances where 

 we have both kinds of leaf on the same plant ; take, for instance, Pyriis trilohata ; 

 trace the transition of the leaves from pinnate to p.ahnato in Authjllis vulneraria or 

 the various species oi Lotus, wherein the lower leaves are pinnate, the upper palmate. 

 The connnon raspbony, Riihus idmis, will fmnish another example ; the lower leaves 

 have sc^'cr.al pairs of pinna?, the upper have but tlu'oe leaflets ; in such cases as this 

 ("and the}' are nmnerous), the tv/o conditions merge one into the other, so th.at it is 

 ditflcult, mthout taking analogy as our guide, to determine whether a temate or a 

 teiiiately divided leaf belongs to the pinnate or to the palmate series. 



The wi-iter has frequently observed in the oriental plane, Plutanm orimtalis, leaves 

 of almost every variety of shape and marginal incision, fi-om oblong or lance-shaped 

 and entire to palmatisict, the latter being the usual fonu of the leaves of this tree. 

 In the entire long leaves there is but a single largo rib, the lateral ones being much 

 less in size, vdiereas in the fully developed condition there are three to five main ribs 

 diverging orto from the other at an acute angle, a short distance above the base of 

 the leaf (hipli- or quintupli-costate). In the ' Linna;a,' vol. xi. 1829, is mentioned 

 the case of some horse-chestnut leaves which had assumed more or less of a pinnate 

 character ; and this season the writer has been fortimate enough to find several pre- 

 senting similar changes from their ordinary condition, and manifesting almost every 

 intermediate stage between pinnate and palmate leaves ; similar instances not im fre- 

 quently occur in the leaves of the common white clover, TrifoUum rcpem. A^'ere 

 it necessary to do so, many additional instances might be cited leading to the same 

 conclusions, that pinnate and palmate leaves are merely modifications of the same 

 typo; that the ternate leaf is an impari-pinuate leaf; the binate leaf is the simplest 



