RELATION BETWEEN THE ALGA AND FUNGUS OF A LICHEN. 505 
1. The gonidium is spherical except when subject to pressure from other 
gonidia. The diameter of fully developed cells ranges from 8 to 15 y. 
2. The chloroplast, in the mature gonidium, has a slightly uneven surface. 
3. After fixing and staining, minute reticulation of the cytoplasm is 
evident. 
4. The so-called pyrenoid (nucleus) is large and central and exhibits a 
distinct structure throughout the substance. Its diameter is roughly one- 
third that of the chloroplast. 
5. A small lateral body surrounded by a light area stains darker than the 
so-called pyrenoid ; it is very conspicuous in many of the preparations ; it 
probably represents the centrosome. 
6. Twin gonidia frequently occur. 
7. There is no vegetative cell division of the gonidium. 
8. The increase in the number of gonidia results from the formation of 
daughter gonidia, autospores (reduced zoogonidia). 
9. We have seen no penetration of gonidia by 'hyphæ. 
List of Papers and Publications quoted. 
1. Bonney, Vioror.—“ A New and Rapid Triple Stain.” Archives Middlesex 
Hospital, vol. xiii. 1908. 
2. Chopat, R.—Matériaux pour la Flore Cryptogamique Suisse, vol. iv. 
tase. 2. 1913: 
3. Danitov, A. N.— Ueber das gegenseitige Verhältnis zwischen den 
Gonidien und dem Pilzkomponenten in der Flechtensymbiose." Bull. 
Jard. Imp. Bot. St. Pétersbourg, tom. x. livr. 2. 1910. 
4 ELENKIN, A. A.—‘ Neue Beobachtungen über die Erscheinungen des 
Endosaphrophytismus bei heteromeren Flechten.” Bull. Jard. Imp. 
Bot. St. Pétersbourg, iv. pp. 25-38. 1904. 
5. Errvixca, F.—' Untersuchungen über die Flechtengonidien." Acta Soc. 
Sci. Fenn. xliv. no. 2. 1913. 
. HzpLoxp, I. I.—' Kritische Bemerkungen über einige Arten der Flechten- 
gattungen Lecanora (Ach.), Lecidea (Ach.), und Micarea (Fr.).” Bihang 
till K. Svenska Vet.-Akad. Handlingar, Band xviii. Afd. 3, no. 3. 1892. 
. Peirce, G. L.—* The Nature of the Association of Alga and Fungus in 
Lichens.” Proc. Calif. Acad. Sci. Bot. vol. i. 1899. 
. SCHNEIDER, ALBERT.—À Text-book of General Lichenology. Bingham- 
ton, N.Y. Willard N. Clute & Company. 1897. 
9. West, G. S.—Cambridge Botanical Handbooks. Algæ, vol. i. 1910. 
for) 
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