594 GRAMINACEAE 



5. Loddon. Plentiful in a field of Sainfoin near Park Place, Messrs. 

 Stanton and Tufiiail. 



The most striking feature of this plant when first seen is the inflorescence, 

 which differs from all other species of Bromus known to me, in that single 

 short stiff pedicels arise alternately right and left of the main rachis, each 

 hearing at its extremity three to five sessile (or in some cases short-stalked) 

 spikelets. To this fact is due the peculiar and strikingly interrupted and 

 compact appearance of the whole inflorescence, which is made up of clustered 

 groups of three to five sjDikelets. This peculiar feature does not obtain in its 

 nearest allies, since in them four to five slender pedicels of various lengths 

 arise at the same level on the rachis, each hearing one or two, rarely more, 

 spikelets ; hence, the inflorescence in these species is more loosely continuous. 



As will be seen, the alliance oiB. interrux>tus is essentially with B. hordeacetis, 

 since the large or inner glume extends half-way to the apex of the sixth 

 flijret (the third on the same side), whereas in B. racemosus and B. commutatus 

 it reaches only to the fourth flower (the second on the same side). The 

 texture and pubescence, too, of the spikelets of B. interruptus are similar to 

 those of B. hordeaceus. The character which at once separates B. interruptus 

 from B. }i,07'deaceiis, B. commutatus, B. racemosus, &c., is to be found (as pointed 

 out to me by the Eev. L. V. Lester, M. A.) in the upper pale (the inner pale of 

 Parnell), which is split to the base, and is usually much shorter than the 

 outer or lower pale. B. interruptus is further distingviished from B. mollis 

 by its being a biennial or sub-perennial growth, by its greater height, and 

 narrow strict interrupted panicle. The fruit of B. interruptus is shorter and 

 darker in colour, with a more conspicuous groove. In B. hordeaceus the palea 

 is more or less adherent to the surface of the caryopsis, than which it is 

 slightly narrower, so that a small margin of the fruit is to be seen. In 

 B. interruptus the pale is only rarely adherent, and then not to the face but 

 to the margins of the fruit. I can see no difference in the lodicules. The 

 suggestion may be made that the split palea may be due to an accidental 

 rupture during the growth of the fruit. That it is not due to this cause is 

 evident from the fact that examination shows that the pales are split from 

 its early flowering stage. Again, the split pale is always to be foxmd in 

 plants having the peculiar character of the panicle already described. 



The history of the species is as follows : In i88S I found what I thought 

 was a peculiar variety of B. hordeaceus in considerable quantity in a barren 

 chalky field in which a crop of barley had been grown the preceding year, 

 but which was then lying fallow. The field is situated on the Lower Chalk 

 formation between Unwell Wood and Blewburton Camp. In the adjoin- 

 ing fields, Bromus hordeaceus, var. glabrescens (Coss.), occurred more frequently 

 than the ordinary form. Subsequently I found the same peculiar form in 

 smaller qviantity in a clover field on the same geological formation on the 

 Oxfordshire side of the river between Goring and Gathampton, 



An examination of our herbarium at Oxford and of botanical works having 

 failed to yield anything like these specimens, I sent a supply to the Botanical 

 Exchange Club in 1888, under the name of B. mollis, var. aggregatus. One of 

 the Berkshire specimens so labelled was sent to Prof. Hackel, of St. Poelton, 

 for his opinion. He quite agreed in considering it a new variety, and while 

 offering to retain my suggested name, thought that the name interruptus 

 would be more suitable, to which I willingly acceded. Prof. Hackel 

 diagnosed it as follows : B. mollis^ L., var. interrupta, Hackel, Panicula 

 brevi, interi-upta, spiculis glomeratis obovato ellipticis, gluma sterili 

 superiore dimidiam spiculam aequante vel superante. Aflfinis B. molli, var. 

 conglomerato, Pers. Syn. i. 96, cujus panicula aequalitur compacta, spiculae 

 angustiores, villosiores. 



For the last seven years I have kept the grass under observation. I find 

 it comes true from seed, and that it is fauiy persistent in its localities, when 



