Alopenmis.] geamine^. 581 



pronounce upon ihem with coniidence on a cursory inspection, an examination of 

 tie root and florets has always enabled roe to decide without hesitation. 



Regarding the root, any specific distinction drawn from that part alone might 

 be open to objection on the ground that the same organ in A . geniculalm is some- 

 limes seen to assume a bulbous character, and that a difference in degree alone 

 can never be safely adduced to establish a permanent distinction. We must, then, 

 have recourse to other marks, and such we find in the structure of the flowers, 

 which in A. bulbosus are narrower than in A. geniculalm, with acute calyx-glumes, 

 the membranous edges of which are emargiuale below the submucronate apex, not 

 rounded at their summit as in A. geniculalm, where the glumes are ciliated with 

 long white hairs upon the back, that are far less conspicuous and much shorter 

 in A^ bulbosus. In both the calyx is clothed with silky hairs, but in A. 

 bulbosus the five ribs are very slrongly marked, especially on the outer side of the 

 floret; these are of a deep purple or black and dilated upwards, the two interme- 

 diate lateral ones green, the dorsal almost mucronate at the point. The bulb- 

 shaped or tuberous bases of the culms in the present species assume that form as 

 completely as Poabulbosa, which never happens with A. geniculatus, the enlarged 

 point of which is rather club-shaped, and destitute of the fine rose-colour so often 

 seen on the former, and well represented by Mr. Curtis. 



Notwithstanding the differences just mentioned, I think it very possible these 

 two grasses may not be specifically distinct, accounting for the characters that 

 mark A. bulbosus, on the hypothesis that the peculiarities of structure which, so 

 united, lead to a conclusion directly the reverse, may, from causes unknown to 

 us, be necessarily inseparable or coexislant ; in other words, the same aberrant 

 principle producing an alteration in one part in the vegetable structure may, fot 

 aught we know, as invariably induce a change on parts of the same plant the 

 most remote. 



4. A. agrestis, L. Slender Foxtail-grass. Vect. Black-grass. 

 Culm erect scabrous above, panicle spiked slender cylindrical 

 acuminate, glumes narrow-lanceolate very acute nearly glabrous 

 united half-way up. Sm. E. Fl. i. p. 81. Br. Fl. p. 516. Lind. 

 Syn. p. 299. E. B. xii. t. 848. Knapp, Br. Gr. t. 16. Host. 

 Gram. Aust. iii. 9, t. 12. Parn. Gr. t. 3. 



Much too plentiful in cultivated fields, amongst corn, clover and other crops. 

 Fl. April — October. 0. 



E. Med. — Extremely common about Ryde, Bembridge, Shanklin, Luccombe, 

 Bonchurch, Sandown, &c. 



W.Med. — Cornfields about Thorley, Wellow, Calbourne. 



An entirely glabrous grass. Root small, fibrous (slightly creeping, M. et K.), 

 annual, emitting numerous slender culms, from about 12 — 24 inches high, erect 

 or geniculate in the lowermost of the hard, shining, cartilaginous joints, where 

 they are sometimes slightly branched ; smooth or immediately below the spike 

 only somewhat roughish, leafless for a considerable distance from the latter down- 

 wards. Leaves distant, short, pale grayish green, finely striated, a little scabrous 

 above and on the margins, with a brownish fold or auricle at base, on long, ribbed, 

 somewhat inflated shealhs, that are open their whole length, and very shining on 

 their inner surface. Ligule short, truncate and torn. Panicle closely spicate, 

 simple or very slightly branched, slender and subcylindrical, a little tapered at 

 each end, acute, from about 2^ to 3^ inches long and about 2 lines wide, either 

 pale green or more usually wholly or in part of a dark purplish red. Spikelett 

 larger than in A. pratensis, closely imbricated, placed in an irregular alternation 

 on the smooth rachis, mostly solitary, but a few of the very unequal pedicels are 

 occasionally forked and bearing a secund spikelet. Glumes joined obliquely to 

 their pedicels at their annular cartilaginous base, a mode of insertion not repre- 

 sented in our published figures of the species, awnless, much compressed, equal, 

 Tnembranous, pointed, concave on the side next the rachis, perfectly united below 

 for above a third of their length upwards, spiuulosely scabrous on the very sharp 



