522 
Note . 
The walls of the mycorhizal cells undergo certain chemical and physical changes. 
In the first region they become lignified, and in the second they are partly dissolved 
by the perforating hyphae. In the third region the walls become thickened, but 
do not undergo any chemical modification. Further, in both the first and second 
regions the wall develops a tubular sheath which always shows a distinct lignin 
reaction. Lignin reaction is also observed in the thick-walled hyphae of the first 
region. 
In the mycorhizal cells the amount of the cytoplasm and the size of the nucleus 
are increased previous to infection by the fungus. After infection the protoplast 
is soon consumed by the fungus in the second region, but in the first region the 
cytoplasm invests the hyphal clump and the nucleus is stretched, often so much as to 
cause fragmentation into two portions. When the clump becomes larger the proto- 
plast disappears entirely. In the third region the cytoplasm increases further in 
amount and acquires a granular and dense consistence, while the nucleus undergoes 
hypertrophy, hyperchromatophily, and various deformations by constriction. The 
constricted portions may be often pulled apart in a stellate form. 
In the mycorhizal cells of the third region there appear prominent bodies which 
may be considered to comprise both secretion and excretion products of the endo- 
phyte. First, light yellowish, oil-drop-like globules (attaining to o-o8 mm. or more in 
diameter) and similar-sized vesicles with a hyaline membrane and containing yellowish 
granules become visible in the cytoplasm. They are both secretion-bodies, or, 
if not, their derivatives, to be consumed later by the host. While these are disappear- 
ing, there occur innumerable, small, hyaline, irregular masses, each in a vacuole of the 
cytoplasm. Afterwards they are thrown into a large common vacuole and by fusion 
form a mass, more or less resembling the so-called clump (‘ Klumpen ’) usually found 
in the digestive cells of many mycorhizal plants. Probably they are derived partly 
from the remnants or ground-substances of the secretion-bodies and partly from the 
undigested wall of the hyphae, and judging from their resistant property they are 
certainly useless excreta. 
The cell of the third region is a metabolic centre of the higher symbiont, where 
the food materials are elaborated. The remarkable alterations in the cytoplasm and 
nucleus are indications of the great activities that are going on in the cell during this 
process ; so that, when the latter is over, the nucleus resumes its original form and 
structure, while the cytoplasm again becomes fibrous and vacuolate. 
The Rhizomorpha, besides forming mycorhiza, behaves towards Gastrodia as 
a true parasite, and under certain circumstances the strand penetrates deeply into the 
tissue of the tuber, then developing as Rhizomorpha subcorticalis. The infected 
tissue collapses and is apparently injured, as may be seen in potato tubers attacked by 
the same fungus. 
Gastrodia multiplies usually by a tuber. It produces long rhizomes from its 
apex or node, upon which are developed stalked offsets. Sometimes the latter are 
produced directly on the node of the mother-body. At the end of autumn, the 
mother-body and the pedicel of the offset undergo degeneration, so that the daughter 
tubercles are all set free separately. 
The association of the tuber with the Rhizomorpha takes place quite occasionally. 
