The Vegetative Anatomy of Molinia caerulea. 51 
wiry haulms usually from 45 to 75 cm. long. The flowers and 
frequently the leaf tips are deep purple, a feature reflected in the 
specific and common names of the plant. 
I. Root. 
If the attempt he made to pull up a Molinia tussock it will 
almost certainly fail, because of the remarkable hold on the soil 
which the plant possesses through its enormous root system. This 
forms an almost solid, tangled mass in the upper layer of the soil 
and penetrates to a great depth, spreading outwards slightly as it 
descends. There are two types of root: cord roots and fibrous 
roots. All the roots springing from the rhizomes are cord roots : 
these are about 1-5 to 2 mm. in diameter and descend from 15 to 
45 cm.; they retain their thickness throughout most of their length, 
tapering only very slightly until within 3 mm. of the tip, when they 
thin off rapidly and terminate in a blunt root-cap; they are so 
numerous that close to the rhizome they squeeze one another out 
of shape, and they are of great strength. Cord roots do not usually 
give rise to branch cord roots : all their branches are fine, branched, 
fibrous roots. These fibrous roots are given off sparingly all the 
way down from close to the soil surface to within two or three cm. 
of the cord root ends, but in the last two or three cm. they arise 
very freely. The fibrous roots are of 0-3 to 0-8 mm. diameter and 
5 to 13 cm. long, and they branch freely in all directions. 
Fig. 2. Cord root of Molinia: transverse section of piliferous layer, 
supporting layer, band of sclerenchyma, and outer zone of cortical parenchyma 
whose walls are not fully thickened ; mycorhiza not shown. For details see 
Text. X 100. 
