•270 
W. O. Howarth. 
whole, moderately humid. Its general habitat is therefore a more 
or less mesophytic one. In the coastal area of Glamorgan it is only 
found along the cliffs well beyond the reach of the sea, and usually 
well protected by higher strata of vegetation such as scrub or open 
canopy wood, or by the lie of the land, from the force of the 
prevailing winds. Inland it is found along roadsides, growing 
amongst the loose stones of less frequented roads, or on hedge- 
banks, especially upon the dust-heaps and sweepings, or even in the 
crevices of old limestone walls. 
Sub-variety tenuifolia, confined to the sea-coast, is either the 
dominant, or a co-dominant plant in the following habitats : — 
(i.) the salt-marsh, where it descends into the Glycerietum and 
is dominant above it, associated with typical halophytes, 
(ii.) the pebble ridge, associated with xerophytes, e.g., Poa 
bnlbosa, var. vivipara. 
(iii.) the hard exposed rocks in scanty soil, calcareous and 
well-drained, associated with halophytes or more extreme 
xerophytes. 
(iv.) the calcareous tufa of the cliff-face. 
i . 
Fig. 2. Subvar. grandiflora. Transition from foliage leaf to propliyll. 
Nat. size. 
In all these situations it occasionally comes under the influence 
of salt water, either by complete inundation or from spray. 
Sub-variety glaucescens, so far as known, grows in the higher 
zones of the salt-marsh and of the littoral, generally out of reach of 
the salt water. Not in Glamorgan ; the nearest point at which it 
has been found to Cardiff is the mouth of the Usk (Mon.) and 
stretching*along the coast well into Gloucestershire. 
III. —Comparative Morphology. 
1. The Branch-system. 
The subvariety grandiflora is loosely sub-caespitose. Its lower 
branches are typically extravaginal, creeping for varying distances 
and then erect, bearing the characteristic prophyll and series 
of scale-leaves, 5—6 (occasionally 9) in number (Fig. 2). Under 
