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except possibly on the first day of flowering, when the corolla is 
still cup-shaped. In no case can this secretion be of importance 
during subsequent stages, when the corolla is spread out. If there 
were here no nectar-secretion at the interstaminal portion of the 
thalamus, the ovaries would be in danger of rapid destruction owing 
to dessication. 
In Ranunculus auricomus the peripheral secretion is still much 
less important. Here often one or two and sometimes all petals ure 
wanting, and with them the nectaries; frequently, moreover, the 
nectaries are rudimentary. 
In the genus Pulsatilla the peripheral nectar-secretion is likewise 
insignificant (its seat is in the metamorphosed anthers of the outer 
whorl). In Pulsatilla vulgaris, P. pratensis and P. vernalis it has 
been observed, that the nectaries frequently do not secrete any nectar; here 
nectar-containing and nectarless plants are found; P. alpina is quite 
free from nectar, according to Scnurz. The nectar-secretion from the 
thalamus is therefore, also in this genus, of primary importance; 
during the flowering period the numerous ovaries are each, as it 
were, covered by a mantle saturated with glucose. 
In the natural order of Malvaceae the true significance of nectar- 
secretion is not less clear than among Ranunculaceae. 
I shall not be able to consider this subject in detail in the present 
communication, but may recall, that BeHrens showed in 1879, that in 
Abutilon, Althaea, and Malva the bottom of the calyx bears a nectary, 
consisting of a large number of closely crowded multicellular 
“Sekretions-Papillen”, which together form a large secreting surface. 
Each “Papille” consists of a large number of cells, placed in a row, 
e.g. in Abutilon insigne 12—14. What Benrens thus describes pro- 
bably applies, as far as my own investigation extends, to all Malvaceae. 
I found these nectaries also in the genera Hibiscus, Kitaibelia, Malope, 
Anoda and Sidalcea. 
Whether in general, bowever, secretion is a constant phenomenon 
in these calyx-nectaries, is doubted by various authors. Of many 
species it is not known whether they ever contain nectar, and of 
other species the accounts are contradictory; in the case of some, it 
might be assumed, that the individuals of the same species differ 
among themselves. Thus, for instance, Kircaner could not find any 
nectaries in Abutilon Avicennae, whereas in this country the same 
plant is so rich in nectar, that the latter can be seen with the naked 
eye. As regards Hibiscus, those species, which are best known in 
Europe, namely #H. syriacus, H. Trionum, and H. esculentus are 
regarded as nectarless. The large flowers of Abutilon are however very 
