255 
Cambium in Monocotyledons. V. 
the shoot apex of Hydrochar is Morsus-ranae , L., and Stratiotes aloides , L., 
and in both these plants I found traces of intrafascicular cambium, though on 
an inconspicuous scale (Figs. 8 and 7). 
Summary. 
This paper forms a continuation of my previous notes on the same 
subject in this Journal for 1917, 1918, and 1919. Further references 
in the literature to intrafascicular cambium among Monocotyledons are 
considered, and certain new cases are recorded. 
It is shown that Lignier was probably mistaken in attributing only* 
phloem-forming activity to the cambium in the petiolar bundle of Arum 
maculatum , since, in the corresponding bundles of the closely related 
A. italicum , secondary xylem is found to be also formed — while Lignier’s 
own figure leaves little doubt that the same process takes place in 
A. maculatum . 
Special attention is paid in the present paper to the search for cambium 
in the slightly developed vascular bundles of the Helobieae, and it is shown 
that the Alismaceae, Aponogetonaceae, and Hydrocharitaceae can now be 
added to the list of monocotyledonous families in some member of which this 
tissue has been observed — an addition which brings the number of such 
families to twenty-two. 
Balfour Laboratory, 
Cambridge. 
Lists of Memoirs cited. 
Andersson, S. (1888) : Om de primara karlstrangarnes utveckling hos monokotyledonerna. Bihang 
till k. Svenska Vet.-Akad. Handlingar, Bd. xiii, 188.8, Afd. Ill, No. 12, 23 pp., two plates. 
Arber, A. (1917) : On the Occurrence of Intrafascicular Cambium in Monocotyledons. Ann.Bot., 
vol. xxxi, 1917, pp. 41-45, three text-figures. 
(1918) : Further Notes on Intrafascicular Cambium in Monocotyledons. Ann. Bot., 
vol. xxxii, 1918, pp. 87-9, four text-figures. 
■ (1919) : Studies on Intrafascicular Cambium in Monocotyledons (III and IV). Ann. 
Bot., vol. xxxiii, 1919, pp. 459-65, seven text-figures. 
Chauveaud, G. (1911) : L’appareil conducteur des plantes vasculaires et les phases principales de 
son evolution. Ann. d. sci. nat., Bot., ser. ix, t. xiii, 1911, pp. 113-438, 218 text-figures. 
Dauphine, A. (1917) : Sur la valeur des formations libero-ligneuses supplementaires chez certaines 
Monocotyledones. Ann. d. sci. nat., Bot., ser. ix, t. xx, 1917, pp. 309-14, one plate, two 
text-figures. 
Gatin, V. C. (1920) : Recherches anatomiques sur le pedoncule et la fieur des Liliac^es. Rev. Gen. 
de Bot., t. xxxii, 1920, pp. 369-437, 460-528, 561-591, sixty text-figures. 
