+ ae UT 
NEW PUBLICATIONS. 245 
ie Lemnaceen. Fine monographische Untersuchung. Von Dr. 
FRIEDERICH HEGELMAIER. (The Lemnacee; a Monograph. By Dr. 
. Hegelmaier.) 4to. With 16 plates. 170 pp. Leipzig: Wil- 
helm Engelmann. 1868. 
This monograph has long been looked for, and is a most creditable 
performance, Dr. Hegelmaier having spared no pains to make it per- 
fect in every way his means and resources would admit. His atten- 
tion was first directed to the Order by the Lemnacee collected in tro- 
pical Africa by that indefatigable and zealous collector, Dr. Welwitsch, 
being entrusted to him for critical examination. The result of this 
examination was published in this Journal, and not only prompted 
Dr. Hegelmaier to pursue the subject further until he had exhausted 
it as far as his present materials would allow, but also induced others 
to follow his meritorious example, and to confide the result of their 
labours to our care for publication. The history of this monograph 
is an apt illustration how British and foreign botany act and react 
upon each other. Some of our local botanists probably did not thank 
us when we filled up a whole plate and a considerable number of pages 
of our Journal with dry technicalities about African Lemnacez, and 
yet to the publication of these they owe indirectly the discovery of a 
genus of Phanerogams absolutely new to the British Flora,—we mean 
Wolfia. 
. Dr. Hegelmaier rejects the opinion of those who incorporate the 
Lemnacee with the Pistiacee (which is undoubtedly a group of Aroi- 
dee, closely connected with the rest of the Order through the genus 
Ambrosinia), and finds a better systematic position for them near 
Zosteracee, which must either be altogether united with the Najadez, 
or be placed iu their immediate vicinity. The nacec represent the 
lowest type of flowering plants, Lemna Columbiana, Karst., being the 
most simple, Spirodela polyrrhiza, Schleid., the most complex organism 
of the group. 
Dr. Hegelmaier enters into full details about the anatomical struc- 
ture and morphology of the Zemnacee, illustrating his views and 
Observations by carefully-drawn plates, and concludes with a syste- 
matic enumeration of all known genera, species, and varieties of this 
ill-understood Order of plants. Altogether Dr. Hegelmaier enume- 
rates 3 genera and 21 species, viz. :— 
