230 



HINTS AND NOTES 



vegetation from which they are derived. The 

 ditch is rather too small to treat in the same 

 way as a river or stream, and to show the 

 zonal arrangement or riparial vegetation, float- 

 ing plants, submerged plants, &c. But where 

 these different types or others (on the basis of 

 Nymph&a, Hippuris, Hydrocharis types, &c.) 

 occur they should be noted. It is as well, if 

 this can be done, to note the absence or 

 presence of Algae, Liverworts, or Mosses (the 

 last on banks usually), as these also throw 

 a light upon the vegetation. 



A list of the plants upon the ditch banks 

 may be made, each bank being kept separate 

 for this purpose. The direction and slope of 

 the ditch, and the character of the soil, should 

 be noticed. 



All ditches do not contain water all the year 

 round, and this should also be stated. Some 

 ditches are perennially dry, and many are 

 filled with thorns cut from a layered hedge. 

 The fact that a ditch has been just cleared out 

 should be noted, and it is important to com- 

 pare the new flora of such a ditch with the 

 result of a former examination. The seedlings 

 that come up will not all live, but all should 

 be observed and put down in the memoranda 

 on the spot. Where bridges and culverts exist, 

 these should be examined. Many lichens grow 

 on the stones or brickwork. 



(c) Hedge and Hedgerow. The hedge forms 

 an artificial barrier to the field or division 

 between two ditches and contiguous fields. 

 It serves two purposes in the main apart from 

 the use it has as a boundary: (i) it acts as a 

 barrier to dispersal of seeds, and thistle down 

 will not travel beyond it usually, hence the 

 affinity of some thistles for the hedgerow ; 

 (2) it serves, as pointed out already, as a 

 retreat for the shade-loving plants ; and we 

 may add (3) it forms a line of distribution by 

 aid of birds, &c., for the dispersal of seeds 

 carried by such agency from one point to 

 another. The hedgerow is thus an important 

 factor in botanical work in the meadow. 



The method of survey may be carried out 

 as for woods. The trees, which are mainly 

 planted like the hedgerow, should be noticed 

 in order of frequency. Their influence upon 

 the plants covered by their overshadowing 

 branches should be noted. It is often very 

 marked. The lichen and moss flora upon 

 such trees may be studied by advanced pupils, 

 and the several aspects taken up by each noted. 

 The hedgerow plants may then be noted in the 

 same way. The direction of the hedgerows, 

 as in the case of the ditches, should be stated. 



Then the ground flora beneath should be 

 noted, as in the case of the plants in the open 

 field, the frequency estimated, and the plants 

 on the different sides should be distinguished. 

 Where the hedge bank has no ditch its flora 

 will differ from that of a ditch bank. 



Climbing plants should be put down sepa- 

 rately, and a distinction drawn between the 

 trailing plants in the hedge bottom and the 

 erect types. 



(d) Ponds. In many if not most fields there 

 are one or more ponds. These isolated tracts 

 of aquatic vegetation should be studied sepa- 

 rately, though as parts of the meadow flora. 

 They are often artificial, but some are natural 

 pools adapted to agricultural purposes. 



The plants growing on the banks may be 

 noted first. Then the vegetation around the 

 margin, such as Sedges growing in the water, 

 but sending up erect stems and leaves. Occa- 

 sionally in large pools there are patches of 

 Reed-mace and Reeds, forming a further type 

 or reed swamp. The floating plants may be 

 studied by themselves, then the submerged 

 and half-submerged types. 



The pupil should be on the lookout for such 

 rare plants as Hydrocharis or Frogbit, or 

 others that give the pool or pond a special 

 character. 



As in the case of ditches, the presence or 

 absence of Alga? and other Cryptogams 

 should be noticed if possible. 



See also Section VIII (Vol. IV). 



SECTION III 

 CORNFIELDS 



Similarity of Cornfields to Fields. The corn- 

 field characters are in many respects similar 

 to those of grass fields, meadow, or pasture. 

 Within the term cornfields are included all 

 types of arable or cultivated land which are 

 subjected to the plough, a factor which is of 



the greatest importance. For this mechanical 

 instrument alone causes all the difference 

 between the close grass of the meadow sur- 

 face and the open broken ground of the 

 cornfield. 



The first characteristic common to ordinary 



