DESIGN AS WITNESSED IN WINGED SEEDS 419 



ment. From the first it is intended that the seed of the goat's-beard shall be wafted about, and it is arranged that 

 the wind shall be the propelling force. The arrangement is not an accidental but a designed one, and it is the 

 employment of a structure in a new and apparently incongruous combination which stamps the act as one of 

 design. The living seed is made the sport of the wind for a definite purpose. The seed cannot move of itself 

 and the wind comes to its aid. The living seed is set in motion by the inanimate but not inactive wind. In other 

 cases, the wind brings seeds from the same or neighbouring trees together. In certain instances insects and birds 

 take part in the flotation and fructifying process. 



In the several cases referred to there is an arrangement whereby nature insures that the male and female 

 elements of plants shall be made to meet and interpenetrate each other. The seeds must be able to fly by the aid 

 of the wind ; or animals must discharge a function which in the absence of wind they alone can perform. Good 

 examples of floating seeds are furnished by the dandelion and by the soft down of the Scotch and other thistles. 



Among trees the ash and plane-tree supply splendid examples of highly-organised, winged seeds. The winged 

 seeds appear to me so important that I describe them separately, and devote a plate to their illustration (Plate xcvi.. 

 Figs. 1 and 4). 



PLATE XCVI 



Plate xcvi. illustrates the remarkable fact that certain winged seeds display many of the structural peculiarities 

 of real wings. Thus the seeds of the ash-tree are twisted upon themselves propeller-fashion as in the wings of insects, 

 birds, and bats ; while the seeds of the plane-tree are characterised by having a right and left wing with a body 

 (the seed) between them. 



The wings of the plane-tree are triangular in shape, and taper from the body in a direction from within outwards 

 and from before backwards. The nervures or stretchers of the winged seeds also radiate from the body of the seed 

 from within outwards and from before backwards as in true wings. 



Fig. 1. — The seed of the ash-tree {Fraxinus excelsior). This seed is twisted in the direction of its length like the blade of the 

 ordinary screw propeller employed in steamships. Its margins exhibit the double figure-of-8 curves of the propeller in a 

 marked manner, and show unmistakable evidence of community of structure (as far as outline is concerned) with the wing of the 

 insect, bird, and bat, and with the chief wing feathers (primaries) of the bird. The seed of the ash is a winged seed, and the object 

 of its screw configuration lies on the surface. It is intended to retard the fall of the seed, and so afford it an opportunity of being 

 wafted by the wind to considerable distances where there is room to plant itself. It is most interesting to watch the shedding of 

 the seeds of the ash-tree in the autumn. If there be no breeze they twirl round and round in a leisurely manner, and fall not far 

 from the root of the parent tree. If, however, a stiiRsh breeze springs up, they are whisked away, in some instances, to quite 

 remarkable distances. The same is true of the seed of the plane-tree, which is the most perfect example of a winged seed known. 



Various other examples of winged seeds might be cited, prominent among which are the thistle-down and goat's-beard, the 

 latter forming a most elegant and perfect parachute, a, b, Seeds of the ash-tree showing a twisted or spiral contour, the margins 

 of each crossing screw-fashion ; c, similar seed from another point of view ; d, similar seed cut across near its attachment. Drawn 

 from nature by the Author. 



Fig. 2. — The little auk {Aptenodytes minor, Linn.). Drawn for the Author from a living specimen by C. Berjeau. In this 

 quaint bird the flying wings are dwarfed and employed as swimming and diving organs, with or without the feet. They are 

 triangular in shape and graduated like other wings ; their small size and want of feathers rendering them useless for flying in the 

 air. They are flexible and elastic, but stiffer than ordinary wings ; a modification necessitated by the greater density of water as 

 compared with air. They are made to vibrate like other wings, and twist and untwist during their action, and make figure-of-8, 

 screw movements. The flight of the bird under water is astonishingly rapid and graceful, as the Author can testify from careful 

 observation. The modified wings of the little auk furnish another example of design in flying structures generally in their relation 

 to winged seeds. 



Fig. 3. — Wings of the kestrel (Falco tinnunculus), seen from above and from below and behind. The lettering is the same in 

 both cases, a, h, e, Posterior margin of the wing, consisting of primary, secondary, and tertiary feathers ; d,.e,f, anterior margin 

 of the wing. 



The wing of the kestrel was drawn from the specimen while being held against the light, and shows how the primary, secondary, 

 and tertiary feathers overlap and buttress and support each other in every direction. Bach set of feathers has its coverts and sub- 

 coverts ; the wing being conical in shape from within outwards and before backwards. The lower figure presents a spiral contour, 

 and shows how it twists and untwists during its action. In certain positions it resembles the blade of an ordinary screw propeller 

 as employed in steamships. Drawn from the natural wing by the Author. 



Fig. 4. — The seed of the plane-tree {Acer pseiido-platanus). This seed is remarkable in many ways : (re) as regards its weight ; 

 (6) as regards its shape ; (c) as regards its venation or nervures. It is a heavy double seed united in the middle, and provided 

 with two very perfect wings, resembling in all respects the wings of insects, birds, and bats (compare with Figs. 2, 5, 6, 7, and 8). 

 The wings have all the characteristics of genuine wings ; that is, they are triangular in shape, are elastic, and taper in two direc- 

 tions, namely, from the root in the direction of the tip, and from the anterior margin in the direction of the posterior margin. 

 They have a thick, semi-rigid anterior margin {a) and a thin, flexible, posterior margin (c), and the venation or wing-supports curve 

 outwards and backwards as in all the w ings described. It would be difticult to produce a more perfect example of design and type 

 in nature than is afforded by this winged seed. It shows that types are not confined to any one division of the organic kingdom, 

 and that the First Cause employs the same or similar means to produce like results. Drawn from nature by the Author, for the 

 present work. 



Fig. 5. The bat ( Vespertilio murinus). In the bat, the peculiarities of the wing of the insect and bird are repeated. Thus, the 



