1908. Proceedings of Irish Societies. 75 



plants being dioicous, the leaves subdulate, lower cell-walls (alone) rarel}? 

 porose, capsule rather small, usually erect and symmetric, longly ex- 

 serted. Dicraniun strictu/ii occurs in tufts usually on old rails and trunks 

 of trees and a very characteristic feature is the fragile nature of the 

 leaves, nearly all of them having the apex broken off. The nerve is 

 narrow at base, about f th of width of leaf, and the basal cells are elon- 

 gate-rectangular, thin walled, 4-8 times as long as broad, gradually 

 becoming shorter above, very shortly rectangular or almost graduate 

 near the summit. The leaf is finely channelled-subulate, entire or 

 faintly denticulate at the margin above. The capsule is oblong- cylindric, 

 but unfortunately all the British plants have been found in a sterile con- 

 dition. Dicraniim strict uni occurs in a very few localities in the English 

 Midland counties, and also on trees in Roslin Wood, 6 miles from 

 Edinburgh, where it was discovered by Mr. W. Evans. 



C. F. Bai,i, showed species of Tillaudsia, a genus of tropical and sub- 

 tropical plants which are mainly epiphytic. The usual type of 

 Tillandsia has broad channelled leaves, sheathing at the base ; the rain 

 pouring upon these leaves runs down into the axils, \vhere it collects, 

 and is then absorbed by means of special glands at the base of the leaf. 

 Tillandsia zisneoides, called the Spanish Moss or Old Man's Beard, is a 

 native of tropical America. The plant is wiry and threadlike, covered 

 with silvery scales one layer of cells in thickness; no roots are produced, 

 but the plant lakes up its food by means of glands which are distributed 

 over both stem and leaves. A section under the microscope showed 

 these glands, which have a centre of cells in form of a sphere divided 

 into quadrants, around which two other rows of cells are arranged. In 

 its native country this plant has been long used as material for packing 

 breakable articles and also orchids. The stems are fairly strong though 

 thin, and are said to be used by the Watchipicket birds for making their 

 curiously-contrived nests hanging on the twigs of trees. 



DUBLIN NATURALISTS' FIELD CLUB. 



February 15 — Geoi^ogicai, Excursion to Carrickmines.— Twenty 

 members and visitors took part in this outing. They left Harcourt-street 

 at 2.15, and on reaching Carrickmines walked across country in a violent 

 hail shower to the Dingle. The origin of this strange steep-sided ravine 

 was explained b}^ the conductor, H. Halliss}', who pointed out the 

 numerous facts which went to prove that it was the overflow channel of 

 a lake formed during the later stages of the Glacial Epoch. From the 

 Dingle the party proceeded to Ballycorus, where near the disused shaft 

 of the lead mine some fine specimens of galena were obtained. Thence 

 to the Scalp, which, as the conductor pointed out, was another example 

 of a glacial overflow channel. After tea at the Scalp the party walked 

 back to Carrickmines station. 



