BOTANY 



These are sometimes so abundant that the straw looks as though whitened 

 with hoar-frost. Another species, Fu/igo septica, known also as ' flowers 

 of tan,' may occasionally be seen on the surface of straw-heaps. It appears 

 as a yellowish white mass, and is sometimes so large as to be compared 

 by casual observers with cauliflower heads. 



In some species the immature condition is different in colour from 

 that of the mature. This is notably the case with some species of the 

 genus Comatricba, which, upon emerging from the substratum, appear like 

 minute white beads on hair-like black stalks. In a day or two the spor- 

 angia turn to a dusky brown. Others again, as Lamproderma, look like 

 minute black beads, which glisten as though covered with varnish. These 

 when mature exhibit iridescent hues. 



A very generally distributed species (Lycogala miniatum), frequently 

 seen in woods in early spring, finds a congenial habitat in decayed logs 

 of wood. When immature it is of a lovely pink or crimson hue, which 

 gradually changes to light brown on arriving at maturity. The heads 

 are sessile, and range from the size of a pea to that of a hazel nut. 

 Another form, known as Trichia persimilis, presents the appearance of a 

 patch of sessile white beads, which when ripe change to a bright yellow. 



Their metamorphoses. In what may be regarded as the initial stage 

 of their life-cycle the Mycetozoa exist as minute spores, usually spherical, 

 each of which contains a speck of protoplasm ; or rather they should be 

 regarded as minute particles of protoplasm which have invested them- 

 selves with a covering of cellulose, usually ornamented with patterns 

 which are constant according to the species. These spores are readily 

 distributed by the wind, and when they fall in favourable situations the 

 spore-covering is thrown off and the contained protoplasm assumes an 

 amoeboid form. 



Eventually a number of these unite and form a plasmodium. This 

 may consist of only a minute expansion, or it may extend to a foot or 

 more in length, presenting the appearance of a network of motile streaming 

 veins. The colour of this varies in different species and genera. It may 

 be yellow as in Badbamia, grey or white as in Pbysarum, pink or rose 

 as in Lycogala, and slate-colour as in Cribraria argillacea. The plasmo- 

 dium may be regarded as the feeding-stage of the organism, and is so 

 undifFerentiated in structure that any portion of it may become a foot, 

 or a mouth, or a stomach, according to requirements. It presents also 

 the phenomenon of circulation, which is of a most singular character. 

 When examined microscopically, the granular contents are seen to flow 

 in one direction for about a minute and a half; then follows a brief 

 pause, after which the streaming motion is set up in the opposite 

 direction ; and this alternate ebb and flow is continued until the organism 

 undergoes a further change of form. The plasmodium-stage may be 

 regarded as that in which conjugation takes place, as it is followed by the 

 formation of spore-bearing organs. 



After continuing in this plastic state for an indefinite period, which 

 may be for weeks or months, the plasmodium contracts itself into com- 



77 



