146 



SCIENCE-GOSSIP. 



with my seed collections I obtained the following 

 results : — 



Number 

 of beeos. 



166 . 



129 . 



41 . 



270 . 



222 . 



Name of Plant. 

 Sparganium ramosum 

 Sparganium simplex (probably) 

 Potamogeton sp. sp. 

 Cyperacece (some 4 or 5 species) 

 Not identified 



Number 

 of Birds. 



Nearly all these seeds were found in the stomach 

 or, rather, gizzard, and but few in the intestines. 

 Subsequent experiments upon a domestic duck 

 showed that this was due to the seeds being 

 usually retained a long time in the gizzard, whilst 

 they pass rapidly through the intestines. The 

 effect of a gorge of soft food is to temporarily 

 lessen the retentive power of the gizzard, and the 

 gravel and hard seeds, which may have been lying 

 there some time, find their way into the intestines 

 and are voided in abundance. A wild duck must 

 often be in a fasting condition during its long 

 flights, and but few seeds would then escape from 

 the gizzard. When it alights on some distant 

 pond or river, whilst ravenously appeasing its 

 hunger, it is at the same time stocking the pond 

 with seeds carried perhaps a thousand miles and 

 more. Not only do seeds thus transported 

 germinate afterwards at the bottom of the pond, 

 but they do so without much delay, as shown by 

 the following experiments. 



In the case of four of the birds the germinating 

 capacity of the seeds was tested, and in three 

 instances very successfully. The seeds of the 

 sedges, of the Potamogetons and of the two Spar- 

 ganiums germinated readily in water, but few of 

 them failing. In fact, a seed of Sparganium ramosum 

 began to germinate only three days after its 

 removal from the bird, and another germinated 

 two days later. In the stomach of one bird a seed 

 of this plant was found fairly advanced in germi- 

 nation, the bird having been dead for at least 

 several days. The readiness with which the seeds 

 found in wild ducks germinate , forms a very strik- 

 ing contrast to their tardiness in doing so when the 

 bird has not intervened in the matter. Of a large 

 number of seeds of Potamogeton nutans passed by a 

 domestic duck in December, sixty per cent, germi- 

 nated during the following spring. Of those left 

 in the vessel from which the duck had been fed, 

 only one per cent, germinated the next spring, and 

 another year elapsed before any number did so. 

 The postponement of germination to the second 

 and third spring and even longer is a curious 

 feature in the life of several water-plants. This 

 subject I am treating with some detail in a paper 

 on " Germination in Ponds and Rivers," which 

 will be presented to the Royal Society of 

 Edinburgh. 



Whilst aquatic birds transport unharmed in 

 their stomachs to distant places the heavier seeds 

 and seed-like fruits of water-plants, the smaller 

 seeds are usually carried adhering to their plumage, 

 legs and feet, and in various ways. The different- 

 modes of seed transportal on the outside oi a bird 

 may be thus grouped. 



1. By inclosure of the seed in mud that has dried on 

 the limbs or plumage. Darwin's striking illustrations 

 of this method of transport are well known, and 

 there can be little doubt in regarding it as often 

 essential for the dispersal of plants with small 

 seeds or fruits that have no special facility for 

 adhering to plumage, such as Hottonia palustris, 

 Montia fontana, Callitriche aquatica, etc. Heavy and 

 large seeds, as those of Nuphar, Ceratophyllum , etc., 

 could scarcely be distributed in this way. 



2. By its being provided with hooks or other similar 

 appendages. The achenes of our species of Bidens 

 as well as the fruits of Galium aparine are familiar 

 examples. If not already recorded, it would be 

 very interesting to catch a bird in the act of 

 dispersing these plants. Such a means of transport 

 is occasionally possible with plants not seemingly 

 adapted to that end. Thus the carpels of Zannichellia 

 palustris can entangle themselves in downy feathers, 

 and sometimes the seeds oiLimnanthemum nymphaoides 

 through the agency of their fringe of hairs become 

 firmly caught. Even the carpels of Ranunculus 

 aquatilis, when hairy on the back, can attach 

 themselves pretty securely to fluffy plumage. 



3. By drying on plumage after dropping from a berry 

 or pulpy fruit. No doubt the seeds of Hydrocharis 

 morsus-rance are often carried about from pond to 

 pond in this fashion, as I pointed out in a paper 

 about two years ago (Linn. Soc. Journ. Bot. xxix., 

 344). This mode of transportal would, however, 

 be more usual with land-plants. After birds have 

 been pecking at the berries of Solanum dulcamara 

 and Bryonia dioica the seeds are often to be noticed 

 dried on the leaves below. 



4. By being adhesive in the dry state. An example 

 is found in Lycopus europceus, the nucules of which, 

 whilst being gathered, stick to the hands ; and 

 they do the same with feathers. This adhesive- 

 ness is increased by slight wetting, and is due to 

 a gummy material that has concreted on the 

 outside of the nucule, mostly on the inner surface." 

 This instance has been given because it affects a 

 plant of great interest to the student of seed- 

 dispersal. Its unlimited means of dispersal by 

 water — for its nucules float indefinitely in sea-water 

 and germinate after years of flotation — explain its 

 ability to cross an ocean. In one of my experi- 

 ments, they germinated freely after floating thirty- 

 three months in sea-water. But its curious habit of 

 occasionally adorning a dust-heap has been some- 

 times a source of perplexity. However, this 

 adhesiveness cannot be compared to the cases of 



