1853.] Linnean Society. 255 



prolongation of its axis, and at the same time causing its scales to 

 be no longer dilated and antheriferous. 



Macrozamia spiralis. 



Mr. Yates next exhibited a small, but perfect specimen of the 

 cone of a male plant, which he lately imported from Sydney. This 

 is probably the first time that a Macrozamia has produced a cone in 

 this country. Together with the recent cone Mr. Yates showed 

 also two old specimens, which had been sent with the living plant by 

 W.S.MacLeay,Esq.,F.L.S., and which that gentleman obtained near 

 his own residence at Elizabeth Bay. One of these two specimens 

 is very remarkable in consequence of being double. At the top of 

 a peduncle of the usual size and appearance are fixed two equal, 

 parallel and perfect male cones. Mr. Yates showed, that some approach 

 to this double formation is occasionally found in the genus Encepha- 

 lartus, inasmuch as the axis of the cone is sometimes bifid near 

 the summit. 



It was also remarked, that the peduncle of Macrozamia bears 

 leafy appendages, and that these have not been found in any other 

 recent genus, but are very conspicuous on the peduncles of the 

 fossil Zamites gigas, which is found in the Oolitic strata near Whitby. 



Read some " Observations on the parasitic habits of Rhinanthus 

 Crista-galli, and its injurious eflfects on the growth of Barley." By 

 Joshua Clarke, Esq., F.L.S. &c. 



These observations were made during the last summer in the 

 parish of Debden, in the county of Essex. The field contained four 

 acres of barley, the soil a stiffish clay ; the Rhinanthus was growing 

 in patches at different parts of the field, some of which were much 

 larger than others, and occupying at least half the surface, by which 

 about two acres of the barley were completely destroyed, and the 

 remaining part of the crop very much injured, both in quantity and 

 quality. The farm consisted of 170 acres, principally clay soil, 

 such as is usually called heavy land ; thirty acres of it were of barley, 

 about ten of which were destroyed by this plant. This loss, combined 

 with other causes, induced the occupier to give it up. 



In regard to the mode by which the Rhinanthus eflS'ects the 

 injury, Mr. Clarke states that the fibres of the roots attach 

 themselves to the fibres of the barley, on which they form small 

 round tubers, or what perhaps maybe more properly called spongioles, 

 which embrace the fibres so effectually, that they suck the juices 

 of the plant so as to starve it, and in most instances ultimately 



