192 THE JOURNAL OF BOTANY 



tulion, wider in proportion to their length, abruptly narrowed to 

 a stout point, which is often recurved ; the margins only slightly 

 and narrowly renexed here and there, one side often being plane. 

 The nerve is stout and narrows but little upwards, filling a great 

 part of the acumen, which is therefore more deeply coloured than 

 the upper part of the lamina, and with more elongate cells, and is 

 also more rigid than in T. Philiberti. T. recognition is nearly 

 always bipinnate only, and is not a variable plant. 



T. Philiberti is, as has been stated, commonest on dry calcareous 

 grassy banks, but is also found in quite marshy places, and also 

 on wet rocks. In characters, as well as in habitat, it is a dis- 

 tinctively variable plant, both in size and branching, and in the 

 form and size of the stem-leaves. These, however, are always 

 more longly acuminate than in T. recognition, sometimes gradually 

 tapering, sometimes more abruptly narrowed, always finely pointed 

 at the apex, and normally ending in the characteristic filiform 

 point, which is, however, much better developed and more persis- 

 tent in moist places than in dry situations. The margins are 

 widely and strongly recurved, the nerve tapers above, and is soon 

 lost in the acumen. 



The true T. recognition Lindb. appears to be distinctly rare 

 with us. It occurs in the older herbaria, e. g. at Kew, from Mat- 

 lock, leg. Sir J. E. Smith, 1820, c. fr.; and from Helks Wood, 

 Ingleton, 1838, leg. W. Wilson. Wilson's No. 395, Muse. Brit., 

 issued as H. delicatulion Linn., is also T. recognition. On the 

 other hand, the specimens at Kew labelled " In old quarry near 

 Malton (Spruce's original locality), Yorkshire, 1854, coll. A. 0. 

 Black," and "Woolsonbury Hill, Sussex, leg. Mitten," belong to 

 T. Philiberti. 



The British forms of this group may be analyzed as follows: — 



[Apical cell of branch-leaves acute, smooth ; perichsetial bracts ciliaie ; 



lj tripinnate tamariscinum. 



(Apical cell of branch-leaves truncate, papillose 2 



(Stem-leaves small, nerve stout in acumen, percurrent or almost so ; 

 bipinnate; perich. bracts not ciliate recognitum. 

 Nerve of stem-leaves narrowing above and lost in mid-acumen ... 3 

 [Acumen of stem-leaves short, simply acute, perich. bracts ciliate; 



oj tripinnate or more rarely bipinnate delicatulum. 



I Acumen of stem-leaves long, gradually tapering to a shorter or longer 



\ filiform point ; perich. bracts not ciliate 4 



. (Stems bipinnate Philiberti. 



(Stems tripinnate var. j^eudo-tamarisci. 



Most of the records hitherto given for T. Philiberti in Britain 

 belong to the var. pseudo-tconarisci ; I have had especially fine 

 specimens of this var. as robust and strongly tripinnate as the 

 larger forms of T. tconariscimon from a tree-stump, Golspie, 

 Sutherland, collected in 1902 by Miss H. M. Crampton. 



It will be seen from the above that British records of T. recog- 

 nitum and T. Philiberti will require revision. 



