GBOWTir E.VPERTMEXTS ON SPEROTJLA AXD PLANTAOO 229 



smooth seeds and seeds with mealiness on the testa, and some two 

 hundred of each kind were sown in two plots at University College, 

 Heading, on May 5th, 1920. By September 1920 the mealy seeds luid 

 l)rodiiced a crop of plants robust in habit, markedly sticky to the 

 touch, and yielding exclusively seeds with mealy testas. The smooth 

 seeds gave rise to plants more delicate in habit and of slightly smaller 

 size, only slightly or not at all sticky, and yielding seed's which were 

 exclusively smooth skinned. The former type of plant is Sperr/tiJa 

 arvensis Linn, and the latter S. sativa Boenn. 



It is evident that both species were growing together in the orip-inal 

 collection, but without hybridising, as otherwise in such a large number 

 of seeds sown there should have been a mixture of forms. The two 

 forms are clearly of specific, rank and not varieties. 



Plantago. 



p. lakceolata. 



In April 1920 a series of experimental cultivations were made at 

 Reading on varieties of this plant. Typical P. lanceolata has long 

 leaves, long peduncles and cylindrical inflorescences. A variety 

 {splicerostacliija Roehl.) occurring frequently in grassy fields and on 

 the tops of walls, has small narrow leaves, shorter peduncles and an 

 inflorescence which is spherical. Its seeds tend to be larger and stouter 

 than those of the typical foi-m. All intermediate varieties between the 

 type and var. sjjltcerostachija occur. The following series of growths 

 was carried out : — 



1. P. lanceolata ; seeds from typical robust form growing on 

 recently disturbed soil, Belfast. 



2. Intermediate varieties with leaves of different sizes and inflor- 

 escences varying from elongated cylindrical to elliptical. Seeds of 

 these were separated into those with thick incurving sides, and thin 

 and scarcely incurving sides. 



3. Typical y^v. sjyhcBrostachya ; seeds' from specimens from grassy 

 fields and tops of walls in the Isle of Man. 



All the above were grown in pots to begin with, and afterwards 

 planted out with about five centimetres between each plant. 



4. Long row of typical P. lanceolata ; seeds from robust Belfast 

 plant. 



5. Long row of typical var. sphcerostaclti/a ; seeds as above. 



In September 1920, the resultant plants were found to be all large 

 and robust P. lanceolata of typical form, with long leaves, long 

 peduncles and c^dindrical inflorescences. No distinction could be made 

 between plants grown from seeds of the type, of intermediate forms, 

 or of the var. splicer ost achy a. 



In April 1920, the experiments were repeated at Armstrong 

 College, Newcastle-on-Tyne, as follows : — 



1. Seeds from robust Reading plant. 2. Seeds from tj^pical speci- 

 men of var. sphcErostacliya from grassy down above Streatle}^ Berks. 

 3. Seeds from similar form from pasture field near Kidderminster, 

 Worcs. 



All were sown so that each plant was about five centimetres from 



