74 CLASSIFICATION ACCORDING TO [CH. 



(1) Motor-cells absent ; vaacvilar bundles feeble and very 

 few. 



Mibora verna. The small leaves are flat, or nearly so, 

 and have three isolated and very feebly developed bundles, 

 devoid of girders or sclerenchyma bands. 



(2) Motor-cells present, vascular bundles of various orders, 

 with sclerenchyma bands or girders. 



* Leaf keeled, and folded— not inrolled. Motor-cells 

 confined to the neighbourhood of the mid-rib. No 

 hairs. 



+ Motor-cells conspicuous and conjoined into a band 

 above the mid-rib. 



Dactylis glomerata. Keel pronounced, with one large 

 vascular bundle and a sclerenchyma band occupjdng its 

 crest. Motor-cells forming one conjoint band along the 

 upper course of the mid-rib only. Stomata on both faces, 

 but no hairs or thick cuticle. Ribs low, and all bundles 

 have feeble girders. A little sclerenchyma at the margins. 

 A few pale cells in the chlorophyll-tissue. 



tt Motor-cells inconspicuous and in two flanking lines, 

 one on each side of the mid-rib. 



Poa trivialis. Keel with sclerenchyma at its apex, 

 and a small band of the same at the margins. Vascular 

 bundles of three orders, isolated, without girders, but 

 with a small band of sclerenchyma above and below. 

 Ridges obsolete. Short hook-asperities above. No 

 thickened cuticle. 



Other species of Poa also come here : I cannot distinguish them 

 by the leaf anatomy ; but P. annua, P. compressa, P. nemoralis and 



