SCIENTIFIC SUMMARY. 
105 
i n the arrangement of crnciferous flowers : — 1st. The oblong plan of calyx. 
2nd. The oblong plan of petals the reverse way to calyx. 3rd. Two sepals 
of the calyx higher on the stem than the other two. 4th. The curious recep- 
tacle on which the smaller stamens grow. The first peculiarity is explained 
thus : as the single stamens are farther removed from the ovary than the two 
pairs are, room must necessarily be made for the bases of these two stamens. 
The cause of the second arrangement is that these stamens are so far from the 
ovary, they push between the pairs of petals and so elongate the petal plan 
the other way. The third form is accomited for by the fact that the two odd 
stamens form a second whorl, which is lower on the receptacle than the pairs, 
and in this way push down two of the sepals. The strange receptacle which 
does not form a circle, is regarded by Mr. Smith as the remnant of one which 
typically forms a complete circle. He says, “ In Megacarpoea polyandm there 
is a receptacle all round the bases of the stamens. Therefore, I suppose, nor- 
mally in all cruciferse there is a receptacle at the base of the second whorl, 
but as the second whorl of stamens is incomplete in nearly all the cruciferse, 
the receptacle is incomplete also. I look, therefore, upon these appendages at 
the bases of the odd stamens as imperfect remains of a receptacle that should 
go all round, but is partially suppressed in the same manner as the stamens 
of the second whorl are suppressed.” 
Progress of the Royal Botanic Society. — At the anniversary meeting of this 
Society, (Professor Bentley in the chair,) the report read by the secretary, 
Mr. Sowerby, showed that the condition of the society is improving. The 
present number of fellows is 2,334, of whom 137 were elected during the 
past year. The receipts from all sources have been most satisfactory. The 
income was £10,781, and the expenditure <£8,059. Is. 
Recent Fall of Manna in Asia Minor. — A letter from JH. Haidinger to 
Sir Koderick Murchison, describing the appearance of a large quantity of 
manna lately (July 6th) observed near Diarberkir, was published some time 
since, and has created a good deal of controversy, regarding the nature of 
manna. We believe, however, that there can be very little doubt that it is a 
species of lichen which like a fungus springs up in the course of a single night, 
and thus gives rise to the notion that it has fallen from the skies. This 
manna is ground into flour a,nd baked into bread, the Turkish name of it 
being Kudert-hogh-dasi, which means wonder-corn or grain. Though used as 
bread, its composition is remarkable ; for it contains more than 65 per cent, 
of oxalate of lime, and has about 25 per cent, of amylaceous matter. This 
substance is evidently the manna of the Hebrews, who gave it the name of 
Man-hu, which signifies “ what is it ? ” from the circumstances of its sudden 
appearance and their previous unfamiliarity Avith it. 
Direction of the Leaves of the Compass Plant. — In the A'merican J ournal of 
Science, Mr. Hill gives the following account of his examination of the leaves 
of thirty specimens of this interesting plant, with a vieAv to discover their 
exact meteorological bearings : Holding a card over each plant with its edge 
parallel to the central line of my own shadoAV, I marked upon the card a short 
line parallel to each leaf of the plant. Measuring afterwards the angle Avhich 
each mark made with the edge of the card, and subtracting from each angle 
the azimuth of the sun for the estimated central time of obseiwation, I 
obtained the following results : — Only one plant, bearing four old leaves. 
