78 



KNOWLEDGE & SCIENTIFIC NEWS. 



[April, 1905. 



MonocleoL Forsteri. 



By Leo Farmar. 



This little plant is a glorified relative of the Common 

 Liverwort, which is so frequently seen growing on the 

 soil of pots in conservatories. 



The genus Monoclea is an interesting exemplification 

 of the evolution of types, forming as it does a connecting 

 link between the liverworts proper (Marchantiaceae) 

 and the scale mosses (Jungermanniace;c). 



It has always been a matter of contention as to which 

 section it belongs, some botanists placing it in the one 

 while others placed it in the other group. 



Professor Duncan S. Johnson, of the Hopkins 

 University, U.S. .A., has recently investigated and been 

 able to throw additional light on the subject,* showing 

 beyond doubt that the hepatic plant in question belongs 

 to the order of Marchantiaceae. 



.Moncclej I-orsteri. Hooker. 



Among other important characters, Professor John- 

 son has discovered that some of the rhizoids, or one- 

 celled roots, ha\e minute tubercles on the inner surface 

 i»f their cell wall, just as in the Liverworts proper. 

 These tuberculatc rhizoids have been overlooked by 

 earlier observers, probably because of their comparative 

 rarity. 



The conclusions arrived at are: "That the thallus 

 (the plate-like vegetative portion) of Monoclea is like 

 that of the Marchantiacea in gross structure, in the 

 mode of growth and branching, in the type of initial 

 cell, and ... in the possession of tuberculatc rhizoids, 

 as well as thin-walled ones, in which latter character 

 Monoclea differs from all described Junger- 

 manniacese." 



He further adds that " the facts of vegetative struc- 

 ture referred to strongly indicate a relationship with 

 the Marchantiacea- and the structure and develop- 

 ment of the reproductive organs seem to me to con- 

 firm this beyond reasonable doubt." 



Monoclea occurs in Jamaica chiefly on wet rocks and 

 banks in the mountain forests. It may be seen grow- 

 ing most luxuriantly in some of the small depressions 

 near \ew Haven Gap in the Blue Mountains. It is 

 distributed also in New Zealand and Patagonia, and 

 was first brought home by a naturalist who accom- 

 panied Captain Cook on his famous voyage. 



The annexed photograph is of a specimen cultivated 

 in the Physic Garden at Chelsea. It is a beautiful 

 object, its delicate dark-green crisp and crested foliage 

 makes it worthy of a place among the choicest of tropi- 

 cal plants. 



The Unfolding of tKe Wings of 



Insects Emerging fron\ the 



Pupa.e State* 



Jiy The Kev. Arthur East. 



XoT the least astonishing detail of the marvellous 

 change from a mummified chrysalis, or an unsightly 

 nymph into a winged insect of more or less surp.issing 

 beaut)', is the manner in which the wings unfold. 

 Looking at the small size of the wing cases in the 

 chrysalis, and contrasting these with the comparatively 

 enormous wings of the perfect insect, it seems im- 

 possible that these wings should have been folded into 

 so small a space. 



•"Ihe Development and Relationship of Monoclea. 

 S Johnson. Dolaniial Gazeltt, SeplemSer. 1904. 



Fig. I.— Crumpled appearance of the wings upon cmerKcnce from 

 the nymph skin. 



The process of unfolding is most easily studied in 

 the case of clear-winged insects, as when the wings 

 are clothed with scales the effects, to which the pre- 

 sent article is intended to draw attention, are marked. 

 I'robably one of the best examples is one of the larger 

 dragon-flies, as the wings are excessively large, and 

 the body, being also bare of .scales, shows clearly the 

 part which it plays in the unfolding of the wings. 



Fig. I shows the appearance of the wings of the great 

 green dragon-fly/lisrhna Cyanea, when emerging from 

 the nymph skin — little more than a lump of damp, 

 crumpled wing material, greyish in colour, ;m(l (|uitc 

 opaque ; yet in three hours these insignificant 

 excrescences have to expand to wings considerably 

 longer than the body, and to become perfectly flat and 

 transparent. 



