ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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hairs are rarely present on the diseased shoots ; when present they are 
usually one-celled. 
(4) Structure of Organs. 
Green Hemi-Parasites. — From a detailed study under cultivation 
of several species of Eujphrasia, Odontites , and Orthantha, Herr E. 
Heinricher * comes to the following general conclusions as to the para- 
sitism of these genera of Rhinantheae. The seeds of Odontites Odontites 
(and probably those of all chlorophyllous parasitic Rhinantheae) are 
capable of germinating independently of any chemical irritation result- 
ing from a nutrient root or from a second living seed, or from living 
tissue. The haustoria of Odontites Odontites (and probably those of all 
parasitic Rhinantheae) are the result of the chemical irritation exercised 
by a nutrient object on the root of the parasite. The parasitism develops 
in a different way in different genera and species. In the case of all 
the species examined ( Odontites Odontites , Euphrasia strict a, Orthantha 
lutea ) single individuals may produce flowers and fruits, when thickly 
sown, without any host-plant. Under these conditions haustoria are 
always formed, but in the presence of a different nutrient plant the 
individuals attain three or four times as strong a development. In the 
case of Odontites Odontites , single individuals sown separately were 
brought to the flowering stage under conditions which excluded the 
possibility of parasitic or saprophytic nutriment. This species is 
characterised by a relatively strong development of root-hairs. It 
reached the flowering stage when grown on two distinct dicotyledonous 
host-plants, Vida sativa and Trifolium pratense , a large number of 
haustoria being formed ; Euphrasia stricta also formed haustoria on the 
roots of Vida saliva. An injurious influence of the parasite on the 
host-plant could be distinctly detected. The seeds of all the green 
parasitic Rhinantheae appear not to germinate before the following 
spring, the spring being the usual time for their germinating. The 
seeds of both Odontites and Euphrasia retain their power of germinating 
for two or even three years, but the period of their actual germination 
varies greatly. 
In the course of his observations, Heinricher criticises unfavourably 
some of the statements of von Wettstein, especially with regard to the 
parasitism of Euphrasia on dicotyledonous plants, and to the retention 
by the seeds of their power of germination. To these criticisms von 
Wettstein replies ; j and in another paper J details further experiments 
with regard to Euphrasia , which lead to the same conclusion, viz. that 
although parasitism is necessary for their full development, individuals 
may produce flower and fruit without parasitism, though their develop- 
ment is then always feeble. 
To the former of these papers Heinricher again replies § 
Polymorphism of the Branches of an Inflorescence.]! — According to 
M. II. Ricome, in a radially branched inflorescence such as that of the 
Umbelliferae, Sambucus , Viburnum, Sedum Fabaria, &c., the different 
branches do not present the same anatomical structure. Those branches 
* Jalirb. f. wiss. Bot. (Pfeffer u. Strasburger), xxxi. (1897) pp. 77-124 (1 pi.). 
t Tom. cit., pp. 197-206. % Oesterr. Bot. Zeitschr., xlvii. (1897) pp. 319-24. 
§ Tom. cit., pp. 442-3. || Comptes Rendus, exxv. (1897) pp. 1046-8. 
