ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
63 
very probable that the Mettenian glands are the primordial form. 
With regard to the stalked glands on the calyx of Plumbago , the 
author states that one can hardly hesitate to affirm that they are ex- 
tremely specialized forms of Mettenian glands seen in typical con- 
dition on the sepals of Ceratostigma, Statice, &c. The presence of 
Mettenian glands is most probably a universal feature in the cotyledons 
of the family. The absence of mucilage-glands from the cotyledons of 
Plumbago , and their invariable presence in the cotyledons of Armeria 
and Statice , point to some occult and exceedingly important functions 
which mucilage performs in the economy of the species of the latter 
genera. 
Besides numerous Plumbagineae, a considerable variety of plants 
having an affinity with this natural order were studied. The glands of 
Frankeniaceae and Tamaricineae most nearly approach them, the latter 
especially bearing, in respect of both form and function, a marked 
resemblance to chalk-secreting Mettenian glands. The Frankeniaceae 
are recognized to be related, although remotely, to the Plumbagineae, 
and it is a remarkable coincidence that they affect maritime situations, and 
are mucilaginous in character. 
Structure of Apocynacege* * * § — According to M. Garcin, it is always 
possible, by microscopical examination, to determine that the least frag- 
ment of stem belongs to either the Asclepiadeae or Apocynaceae, the most 
important common characteristic of these two orders being the presence 
of unseptated laticiferous tubes. The structure of the bast indicates an 
alliance with the Solanaceae, Loganiaceae, and Convolvulaceae. The 
more important points in the anatomy of the Apocynaceae are described 
in detail, and the variations which occur within the order. 
Campanulaceae and Compositae.f — Herr J. Seligmann discusses the 
differences and resemblances between these two natural orders in the 
structure of their tissues, and asserts that the phenomena point to a near 
affinity between the two ; the most important difference being the absence 
of tracheid-fibres in the Compositae. The Lobeliaceae present, in many 
respects, a connecting link between the Campanulaceae and the 
Compositae. 
(4) Structure of Organs. 
Variations in the Flower of the Snowdrop.J — Prof. G. Stenzel 
describes the variations which occur in the flower of the snowdrop in the 
following points : — The number of perianth-leaves and stamens, whether 
in the way of increase or diminution — this usually takes place symmetri- 
cally in both sets of organs ; or in the occurrence of two flowers in the 
same sheath — this is the result of fastigiation, not of chorisis. 
Nectary-covers.§ — According to Prof. F. Delpino, the chief function 
of the lid or cover with which the nectaries of many flowers are provided, 
is to protect the honey against the visits of hurtful insects, such as antSo 
The fact that they not unfrequently occur in pendent flowers refutes 
* Ann. Soc. Bot. Lyon, xv. pp. 197-448 (2 pis.). See Bot. Centralbl., xliii. 
(1890) p. 207. 
t Bot. Centralbl., xliii. (1890) pp. 1-5. 
j Luerssen u. Haenlein’s Biblioth. Bot., Heft 21, 1890, pp. 1-45 (2 pis.). 
§ Malpighia, iv. (1890) pp. 21-3. 
