17 
1 Ib. of pure seed contains, on an average, 2,400,000 grains. 1 acre of ground re- Amount of 
quires, on an average, 17'/2 Ibs. of seed containing 48 °/o pure and germinating = 8.4 lbs. seed per acre. 
of pure and germinating seed, 
Unless for ornamental purposes, Poa pratensis is neyer sown alone. In mixtures for Mixtures. 
temporary and permanent leys, especially on dry soils, it is used to form »bottom grass«, 
It is not suitable for clover-mixtures. After sowing, the seed should never be covered, but 
only rolled, because it germinates better in Hight than in darkness. 
Poa pratensis closely resembles Poa trivialis and is often confounded with it. It is distinguished Distinguishing 
by the following characters: — the stolons are underground; the colour is darker; the ligule is short characters. 
and obtuse; and the culm is smooth (see table, pp. 82, 83). 
—————E——E— 
AIV. Rough-stalked Meadow-grass. 
Poa trivialis, L. 
. Entire plant shewing the mode of growth and the panicle. Explanation 
. A three-flowered spikelet before flowering. of plate. 
,  &. A two-flowered spikelet broken, shewing a pair of pales suspended by the web of woolly hair, 
, 0 A pair of pales detached, side-view, shewing the web of hair attached only to the base 
of the outer pale. 
: ‘f %. Spikelet in flower. The reproductive organs of both flowers are visible. 
,  & The lodicules, pistil, and basal portion of the upper pale. 
, 6. A group of false fruits (seeds) shewing the entangled webs. The pales to the left are 
rudimentary and must therefore have occupied the apex of a spikelet. 
, 7. False fruit (seed), the »web« removed, ventral surface. The margins of the lower and 
the two keels of the upper pale are seen. The middle line of the inner pale is pressed 
down into the deep groove of the caryopsis. 
, 8. False fruit, side-view. The lower pale is acute and the ribs are prominent on its surface. 
» 9. False fruit from which the outer pale has been removed, seen partly from the side and 
partly from the ventral surface. 
,, 40. Caryopsis, dorsal surface, shewing the embryo. 
,, 44. Caryopsis, side-view. 
,, 12. Caryopsis, ventral surface; shewing the hilum and the deep groove. 
, 13. Transverse section of the caryopsis grooved above (ventral) and rounded on the back 
(dorsal). 
144. Transverse section through the uppermost sheath of a leafy branch, showing two entire 
Jeaf-sheaths surrounding a folded leaf-blade. 
, 415. Transverse section of a leaf-blade. 
, 416—18, The long, acute ligule of a culm leaf, 
19. The short ligule of a radical leaf, 
= 
OR 
— > 
Botanical description. The branches of this grass are all extravaginal and bear green leaves; Botanical 
they vary however in the extent of their horizontal curve. Some ascend directly into the air to form description. 
a loose tuft (fig. A to the left). Others take at first a horizontal direction along, never beneath, the 
surface of the ground; ultimately these bend up and ascend into the air, From the nodes lying on the 
