42 
Arber . — On the Occurrence of 
Swedish, have perhaps scarcely received the attention they deserve. 
This author found that intrafascicular cambium was extremely widespread 
in the young tissues of Monocotyledons, and that the development of the 
bundle in this group was, in this respect, not nearly so divergent from that 
in the Dicotyledons as had previously been supposed. Her work was not 
confined to seedlings, as some citations from it might seem to indicate. She 
figured the following cases, some of which showed a fair development of 
cambium, while in others merely a trace of meristematic activity occurred: 
Triglochin maritimum (stem), Cyperus alternifolins (leaf), Zea Mays (leaf- 
sheath and stem), Amomum sp. (stem), Typha sp. (leaf), Brahea filamen - 
tosa (petiole), Platanthera bifolia (stem), Allium senescens (leaf), A. nutans 
(leaf), Lilium Martagon (stem), L. candidum (stem), L.japonicum (stem), and 
Dracaena sp. (stem). She drew attention to the similarity of the bundles of 
Ranunculus repens and those of Lilium ) and figured them side by side for 
comparison. 
Ten years later Gravis 1 recorded the occurrence of intrafascicular 
cambium in the stem and leaf of Tradescantia virginica. The cambium, 
which is extremely clear in the young stem bundle, leaves no trace when the 
adult state is reached. 
In 1899 Queva 2 described the most remarkable instance of intra- 
fascicular cambial activity yet recorded for Monocotyledons. In Gloriosa 
superba tubers are formed and filled with starch in one season and depleted 
during the next year. The bundles thus pass through two periods of 
activity separated by a period of rest. In the second period of activity, 
xylem and phloem elements are formed from the cambium. This resump- 
tion of cambial activity, after an interval during which cell division has been 
in abeyance, is, so far as our present knowledge goes, unique among Mono- 
cotyledons. 
T. G. Hill, 3 in 1900, rediscovered and figured the intrafascicular 
cambium of the stem of Triglochin maritimum — one of the cases which 
Andersson had described and illustrated at an earlier date. 
The Cyperaceae and Gramineae — families in which Andersson had 
already recorded the existence of cambium — received further attention from 
this point of view in 1906. Plowman 4 noted, in this year, that he had 
observed evidence of cambial activity in the internodal bundles of practically 
all the examples of the Cyperaceae which he studied. In the same year 
Chrysler 5 drew attention to its occurrence in the stem and leaves of more 
than twenty species of grasses. The development of cambium just above 
the nodes is associated by this author with the power, which the grasses 
possess, of bending upwards when the stem is laid horizontally. 
1 Gravis, A. (1898). 
3 Hill, T. G. (1900), PI. IV, Fig. 5 . 
5 Chrysler, M. A. (1906). 
2 Queva, C. (1899). 
4 Plowman, A. B. (1906). 
