Notes . 
176 
guard-cells of the same stoma do not behave alike. In some cases 
one, in others both, guard-cells contain two nuclei, but the cell-wall 
between them has failed to appear ; and all transitions may be 
observed until each guard-cell is divided transversely into two cells, 
each of which contains a nucleus. I have never seen further division 
occurring, nor in any direction except transversely. 
This peculiar behaviour of the guard-cells in the fruit seems to 
be confined to this species of Iris ; I have frequently examined other 
species, but hitherto without success. In Iris pseudacorus it is of 
very common, but by no means of universal, occurrence, as I have 
failed to find it in certain specimens; still, as I believe there exists 
no mention of such a division of the guard-cells of stomata, this case 
seemed deserving of being put on record. 
J. BRETLAND FARMER, Oxford. 
Postscript. — Since the above has been in type I have met, in 
W. P. Schimper’s Recherches sur les mousses, 1848, PL VIII, Fig. 22, 
with a figure showing division of a guard-cell of a stoma in Poly trichum 
commune. In the text, however (p. 165), the author contents himself 
with a bare mention of the fact, without offering any explanation of it. 
MYSTROPETALON THOMII, HARV.— The nearness of 
affinity of this genus of the Balanophoraceae to such a genus 
of the Santalaceae as Myzodendron suggested to me an examina- 
tion of its ovules, to see if there was any indication of an elongation 
of the embryo-sac such as occurs in Loranthaceae and in Santa- 
laceae. I was able, through the kindness of Mr. Jackson, to 
examine spirit-material of the plant in the museums of the Royal 
Gardens, Kew. The material gathered many years ago at the Cape 
of Good Hope by Dr. Harvey is, unfortunately, not in a condition to 
permit of a detailed microscopic examination, but is yet sufficiently 
well preserved to allow me to say that there is in Mystropetalon a 
secondary elongation of the embryo-sac at both synergidal and 
antipodal ends of such a nature as to bring about conditions for the 
nursing of the embryo similar to those found in Myzodendron. 
Probably examination of other Balanophoraceae would yield similar 
results. I am now waiting for fresh material of the plant, which 
Mr. Bolus is attempting to get from ‘ About Caledon Baths.’ 
T. JOHNSON, South Kensington. 
