ANAGALLIS ARVENSIS. 141 



light. The seeds, Fig. i6, are of trigonous shape with three angles 

 and three semi-convex facets. The testa, or outer covering, is 

 tubercular, and under the microscope appears to be composed of 

 a number of pellets closely joined together. It is a good object 

 for polarised light, which reveals a series of short prismatic crystals 

 that are not detected except by the use of the polarising prisms. 

 The testa is the only portion of the plant which contains crystals 

 (see Fig. i8, b). The plant instinct in the distribution of seeds 

 is an interesting study. The mature blossom is upright, but as it 

 fades and the capsule matures, the spiral tissue of the stem 

 contracts and curves downward until the capsule faces the earth, 

 the lid falls of and the seeds are discharged upon the ground. In 

 closing the life history of this little flower, I shall refer to its 



Fertilisation. Sir John Lubbock, in his interesting book on 

 " British Wild Flowers considered in relation to Insects," calls 

 attention also to the sleep of flowers. He suggests that the habit 

 has reference to the visits of insects for the purpose of fertilisation. 

 Flowers which require night-flying insects would have no occasion 

 to open in the day; those which require such insects as bees would 

 not have any advantage by opening at night. He states that the 

 habit of closing preserves to the plants the honey and pollen, of 

 which other insects than those useful to their fertilisation would 

 deprive them. It is, however, questionable if the opening and 

 closing of the Anagallis arvejisis depend upon this agency alone, 

 because Sir John Lubbock states in another part of his book, that 

 in this particular flower the stamens and pistil ripen simultaneously, 

 and that the flowers contain no honey. 



He further states that the plant is seldom visited by insects, 

 and that consequently it depends upon self-fertilisation. I am, 

 therefore, inclined to think that the opening and closing of the 

 flower is not perhaps so dependent upon the heat of the sun as the 

 above quotation from Sachs may at first lead us to infer, especially 

 when we remember that the Anagallis sleeps so soon after noontide 

 heat. May we not rather look back upon the phenomenon as 

 another instance of vegetable sagacity ? The abundance of spiral 

 tissue in the corolla has its special oftice to fulfil just at the right 

 time and for a particular purpose, namely — the self-fertilisation of 

 the ovules. The corolla lobes, stamens, and stigmatic surfaces are 



