graves: a botanical trip to north wales 171 



combination held full sway near the tops of some of the peaks, or 

 above about 2,000 feet altitude. Higher up they too disappeared, 

 and the willow mentioned above was the sole member of the 

 phanerogamous vegetation. 



Fig. 3. A lake in the Nant Ffrancon Valley. 



• A gorgeous sight awaited us in one of the mountain tarns, where 

 the cosmopolitan marsh marigold, Caltha palustris L., flourished 

 with all the lavish richness of golden yellow color which American 

 plant lovers know so well. In this same little lake, Isoetes laciistris 

 L., Lobelia Dortmanna L., the latter of \vhich I had collected the 

 year before in a Connecticut pond, Littorella laciistris L., and 

 Ranunculus Flamptula L. grew in abundance. In other tarns, 

 Menyanthes trifoliata L. was found to be plentiful. 



One of the rarest plants in Britain, Lloydia serotina (L.) Sweet, 

 was found high up in a narrow gorge. This is a small liliaceous 

 pjant with morphological characters closely resembling those of 

 the tulip, but with a spreading perianth. It bears a single small 

 white flower, with the perianth segments showing longitudinal 

 reddish lines. Known in Britain only in some of the highest 

 Welsh mountains, it also inhabits the high mountain ranges of 



