BY E. breakwp:li>. 45 



Panicum flavidum Retz. 



Hah. — New South Wales, Queensland, and tropical Asia. In 

 this State, it is most common on the better class of soils. 



Growth-form. —Tufted, bases of stems knotted but not bulbous; 

 adventitious roots strong, long, and not typically fibrous. Leaves 

 rigid, and often broad and scabrous. 



Leaf-anatomy (Fig. 2). — The stomata (St.) are confined to the 

 dorsal surface, while the bulliform cells are arranged in groups 

 of six or seven, and occur in depressions. 



The bundles are of three kinds (M.B^), open below, but bounded 

 on the dorsal and ventral surfaces by hypoderma. The secondary 

 bundles (M.B3) are completely enclosed by chlorophyll-bearing 

 cells, and not bounded by hypodermal fibre. Tlie bundles(M.B4) 

 are open on the ventral surface, but bounded by hypoderma only 

 on that surface. The bundles of this series contain xylem as 

 well as phloem. The xylem of the bundles is better developed 

 than in any of the other Panicums examined. 



The midrib is well developed, and contains three primary 

 bundles (M. Bj), and two bundles (M.B4) of an intermediate type. 

 The uncoloured parenchyma-cells are in two or three bands. 



The hypodermal development of the leaf is large, and raises the 

 surface at these points above the general level of the epidermis. 



Conclusion. — The dorsal position of the stomata, the bulliform 

 cells, the well developed hypoderma, the large and numerous 

 xylem-elements, are the principal xerophytic features of this 

 grass. 



Themeda avenacea Hackel. 



Hah. — Throughout Australia (except Tasmania). In this 

 State, it grows principally on the black soils of the northern 

 tablelands and north-western interior. 



Groivthform. — Very tussocky, with well developed root-system. 

 Bases of stems not bulbous. Leaves extremely coarse and rigid, 

 mostly confined to the base of the plant. 



Leaf anatomy (Fig. 3). — The epidermal cells are small. The 

 stomata are confined to the dorsal surface. Groups of bulliform 

 cells, in series of five or six, occur. 



