ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 453 



Anatomy and Diseases of Aurantiaceae.* — In a very exhaustive 

 monograph of the twelve genera which constitute the Aurantiaceas, 

 Dr. O. Penzig discusses the morphology of the various organs, the 

 physiological relationship of the species, the fruits and the organic sub- 

 stances found in them — citric acid, an ethereal oil, calcium oxalate, 

 hesperidin, aurantiin, murrayin, seglein, decumanin, and limonin — and 

 the diseases to which the crop is subject. 



Of parasitic and saprophytic fungi on the Aurantiaceae, Dr. Penzig 

 enumerates 190, of which 12 belong to the Hymenomycetes, 4 to the 

 Discomycetes, 109 to the Pyrenomycetes, 56 to the Hyphomycetes, and 

 2 to the Phycomycetes. There are, besides, 1 Myxomycete and 12 sterile 

 forms of mycelium. 



Morphology and Anatomy of Loasaceae.j — Herr M. Greinert de- 

 scribes the peculiarities of this order, including about 100 species, 

 especially in relation to the structure of the seeds, the germination, and 

 the nature of the hairs. The embryo is always elongated, straight, and 

 placed in the middle of the endosperm. The cotyledons are fiat and 

 plano-convex, and always lie with their flat sides in contact. The endo- 

 sperm always contains large quantities of oil, but never starch. The 

 very characteristic hairs are of different kinds : unicellular and multi- 

 cellular, glandular, stinging, sharp-pointed, barbed, and silky. The 

 anatomy of the stem and leaves shows a great uniformity throughout the 

 order, although some of the species are herbaceous and others climbing. 



Polymorphism attributed to certain generic groups. J — M. F. 



Crepin queries whether the exceptional polymorphism which is attributed 

 to certain genera is not more or less of a fallacy. The genera Hieracium, 

 Mentha, Bubus, and Bosa are often quoted as examples of groups where 

 excessive polymorphism exists, but these genera have been carefully 

 Btudied by many generations of botanists. The degree of polymorphism 

 accorded to a genus varies directly in proportion to the amount of ana- 

 lytical examination which has been devoted to the species and varieties 

 of that genus; and the author considers that the exceptional poly- 

 morphism attributed to certain genera, and the stability of form attributed 

 to certain other genera, have as yet not been sufficiently proved. 



£. Physiology.§ 

 (1) Reproduction and Germination. 



Heterostylism and Self-fertilization. || — Herr W. Burck finds a 

 transition between dimorphic and trimorphic flowers in species of Con- 

 iiarus and Averrlwa. C. Banlcensis and diversifolius are dimorphic, with 

 rudiments of a second internal whorl of stamens which do not produce 

 pollen. C. falcatus is trimorphic, but the inner whorl of stamens has 

 smaller anthers and smaller pollen-grains. These anthers do not open, 



* Penzig, O., 'Studi hot. sugli Agrumi,' 590 pp. and 58 pis., Rome, 1887. 



t ' Beitr. z. Kenntniss d. morph. u. anatom. Verh'altnisse der Loasaceen,' 58 pp. 

 and 1 pi., Freiburg i. B., 1886. See Bot. Centralis, xxxiii. (1888) p. 204. 



% CR. Soc. R. Bot. Belg., 1888, pp. 39-47. 



§ This subdivision contains (1) Reproduction and Germination; (2) Nutrition 

 and Growth (including Movements of Fluids) ; (3) Irritability ; and (4) Chemical 

 Changes (including Respiration and Fermentation). 



|| Ann. Jard. Bot. Buitenzorg, vi. (1887). See Bot. Centralbl, xxxiii. (1888) 

 p. 260. 



