SPIRAL ARRANGEMENTS IN PLANTS 23 



PLATE IX (continued) 



B. Stem, a, of vegetable marrow with three tendrils ; b, mature tendril growing fi'eely in space wliich has coiled upon itself 

 to form a single cone-shaped left-handed spiral. 



0. Stem, a, of vegetable marrow having three tendrils, b, c, d; b, young tendril which has uncoiled and straightened itself; 



c, mature tendril in the act of re-coiling and forming a left-handed spiral ; d, e, f, mature tendril which has re-coiled and forms a 

 douljle or reversing spiral : at d, the spiral is left-handed ; at e, the spiral is reversing, and at /, it is right-handed. The power 

 possessed by plants of forming right and left-handed and double or reversing spirals is a feature of extraoidinary inlrerest, as proving 

 original endowment. In Fig. C, as in Figs. A and B, the tendrils are giowing freely in space : the single light and left-handed 

 and double reversing spirals are therefore natural formations, and are not due to inherent irritability or stimulation caused by coming 

 in contact with anything living or dead. Similar remarks are to be made of animal tissues : muscles, nerves, l)ones, horns, claws, 

 teeth, shells, &c., all assume spiral forms quite apart from either irritation or stimulation. 



Drawn three-fourths natural size, by C. Berjeau from fresh specimens collected by the Author. 



Fig. 2. — Species of Medicago. Shows flattened spiral pods (legume) ; na', spiral stem ; /)//, leaves ; r, back view of spiral pod ; 



d, side view of pod ; e, front view of pod ; /, pod opened out, seen from behind and laterally. Here there can be no question as to 

 inherent spiral endowment, as the pods are not, and never have been, in contait with anything but air. Irritability and contact with 

 foreign bodies take no part in the spiral formations. Drawn natural size, by C. Berjeau from fresh specimen collected by the Author 

 at Ronda, Spain. 



Fig. 3. — Shows striking examples of spiral formation in plants. 



A. Scliubertia {I'hynianthus). Si em forming right-handed spiral. 



B. Glorioxa saperba. Leaf terminating in spiral tendril. 



C. Croton (Cndiseum). Leaf forming right-handed spiral. 



D. Orchid (Cypripediina). Right-handed spiral. 



E. Clematis (C. mnntana). Leaf stalks form right and left si)irals round alien stems. 



F. Convolvulus (C. arvrnsis), forming right-handed spiral round gooseberry twig. 



G. Honeysuckle (Loniceni Pi'riclymeninn), winding from left to right. 



H. Two honeysuckle stems entwined and forming left-handed spiral as in the human umbilical cord (Plate xii., Fig. .3, ]i. 27), 

 and spiral intestine (Plate xii.. Fig. 4). 



Drawn by C. Berjeau from fresh specimens collected by the Author. 



PLATE X 

 Plate X. illustrates spiral formations in the stems, tendrils, and fruit of plants. 



Fig. 1. — Spiral stems and tendrils of the passion-flower (Passiflora alata). Shows right and left-handed spirals, double reversing 

 spirals, and spiral tangles. 



A. a, Stem forming right-handed .spiral ; b, revolving summit of passion-flower with young coiling tendrils ; r, i-, e, mature 

 tendrils forming single and double reversing spirals. 



B. d, e, Stem of passion-flower twisting from left to right and forming right-handed spiral ; /, /, double reversing spiral and 

 spiral tangle ; g, h, typical example of double reversing .spiral tendril. 



C. I, j', Right-handed spiral formed by stem of passion-flower; k, I, m, n, o, 2), well-marked examples of double reversing .spiral 

 tendrils. The stems and tendrils of the passion-flower are natural .spiral formations. The nature and degree of spirality exhibited by 

 them are due to inherent endowment and not to irritability and external stimulation. This follows becau.se the stems and tendrils 

 curve and twist when not in contact with anything save the air. The tendrils even reverse their spirals when similarly circumstanced. 



Drawn by C. Berjeau from fresh specimens collected by the Author. 



Pig. 2. — Specimens of fresh hops (Hinmilvs Liipiilim) sent to the Atithor from Kent. Drawn by C. Berjeau. 



A. Spiral bundle of hop stems. The stems twine into each other and form left-handed spirals. 



B. Single hop stem forming a left-handed spiral. 



C. Another portion of the same stem forming a right-handed .spiral. It is not possible that any form of extraneous stimulation 

 could produce right and left-handed spirals in the same stem. This can only be referred to design and original endowment. 



Fig. 3. — A. Spiral stems of Tecoma (Bignonia) twisting and forming a right-handed spiral. 



B. Sprig of Sweet Pea (Lathijrus odomttis) with tendrils forming right and left-handed spirals. 



C. Stems of Asparagus {Asparagus plumosns) twisting spirally into each other. The twist is in an opposite direction to that 

 figured at A. They form a left-handed spiral. 



Drawn by C. Berjeau from fresh specimens collected by the Author. 



Fig. 4. — A, B. Diagrams illustrating the spiral arrangements of the leaves and fruit of a plant. At A the divergence between every 

 two leaves is f , as shown by the upper circle of the diagram, where the space between 1 and 2 includes three of the seven divisions. At 

 B, the divergence between every two leaves is ], as indicated by the marks on the circle. C!. Spiral fir cone— the spirals running in 

 two principal directions, as shown by the darts ; the one spiral being more vertical than the other. The secondary spirals indicate the 

 difference between each scale of the cone in a single spiral. The cone is composed of numerous scales, which are metamorphosed leaves 

 aiTanged on a common axis and covering the seeds (after J. H. Balfour). 



