THE PLANT AS A PARENT 



939 



by the composite plants are contained in 

 vessels pro\-ided with appendages to 

 enable the processes to float away on the 

 breezes. These devices reach their per- 

 fection in the various members of the 

 Thistle family, which surround their seeds 

 with the most perfect flying apparatus 

 imaginable. Anyone who has watched a 

 clump of Thistles on a breezy autumn 

 dav must have marvelled that the whole 

 world has not long since been crowded 

 out by these aggressive weeds. Every 

 puff of wind raises the downy seeds from 

 the plants, and away they go scudding 

 over the countrv' until they settle in 

 some situation from which they cannot 

 escape. The seed vessels of the Thistle 

 often rise to a height of thirty feet in the 

 air, and when at this elevation it is not 

 unreasonable to suppose that they travel 

 a mile or more before finally settling down. 



Following after the Thistle there is a 

 whole host of plants producing seed 

 vessels which have tufts or crowns of hair 

 as attachments. The pretty little para- 

 chute-Hke device of the Dandelion seed, 

 the hairy tufts of the Willow Herb 

 and Bulrush vessels, all materially assist 

 in the dispersal of the plant's progeny 

 over a wide area. A httle plant, common 

 enough in some meadows, known as 

 Thrincia hirta, produces two kinds of 

 seeds ; one is provided with hairy appen- 

 dages, the other is not. The former are 

 specially adapted for travelling over a 

 considerable distance, whilst the latter 

 are for the perpetuation of the species 

 nearer home. 



The seeds of many trees, although they 

 cannot rival the length of flight accom- 

 plished by the Thistle, are by means of 

 their formation wafted to a considerable 

 distance. If the fruit of an Elm be 

 examined a curious wing-like expansion 

 is found, which when a moderate breeze 

 is blowing enables the heavy seed to 

 float away from its parent. In common 

 with those of the ]\Iaple, the Sycamore 

 seed vessels go round and round, and 

 thus retard the rapidity of their fall to 

 the ground. The golden long-stemmed 

 blossoms of the Lime are developed with 

 a green bract, and this appendage remains 

 until the late summer. When the ripen- 

 ing of the seed has cf)me about the whole 

 process is detached from the tree, and as 



soon as it is in the air the use of the bract 

 becomes apparent. The seed capsules 

 are heavy, and pull the device into an 

 upright position, in which state, as it falls, 

 it commences to revolve with amazing 

 rapidity. This induces a very leisurely 

 fall, and, of course, all the while the process 

 is sinking it is being carried farther afield 

 by the breeze. The small seeds of the 

 Birch and the Elm are surrounded by a 

 membranous expansion which, as the 

 vessels leave the tree, catches the wind 

 and away they sail — not to settle down, 

 perhaps, until they are some hundreds 

 of yards awaj' from the starting point. 



Not a few plants rely upon water as 

 the means b}' which their seeds are dis- 

 tributed. The strange double Coco Nut, 

 the fruit of a Coco Palm, was a tremen- 

 dous puzzle to early navigators, who 

 very often found specimens floating in 

 the sea many miles from the nearest 

 land. The question was not definitely 

 settled until the discovery of the 

 Seychelle Islands, when the palm bearing 

 the nuts was identified, thereby clearing 

 up a great mystery. It is by ocean 

 currents that the common Coco Nut 

 has been distributed so widely among 

 the Pacific islands. Almost the first 

 tokens of vegetation on the coral reefs 

 are the Palm trees, which appear on the 

 smallest patch above high-water mark. 

 The preparation of the Coco Xut for its 

 long sea-voyage is a matter to which the 

 plant has given special attention. In 

 the first place the embryo and supply of 

 food material are encased in a singularly 

 dense shell, but outside of this is an 

 enormous fibrous mass completely envelop- 

 ing the nut itself. The distance over 

 which these seeds will float is extra- 

 ordinary, and were it not for the hmited 

 climatic range the species could not fail 

 to ha\'e been established all over the world 

 long ago. It is a well-known fact that 

 seeds of various plants indigenous to the 

 West Indies are not infrequently found 

 on the north-west coast of Norvvay, where 

 they have been swept round b}'' a branch 

 of the Gulf Stream. 



In Britain the movements of water- 

 borne seeds are to be observed in the case 

 of many plants which grow on the banks 

 of rivers or streams. The charming 

 Snowflake, a plant which is probably not 



