662 



THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. 



stipe, and a flat, expanded leaf, deeply lobed like a hand. It is often met with two 

 metres in length. The leaf is of a leathery consistency, and the flattened or cylin- 

 drical stalk has a wide parenchymatous cortex and central "medulla", in which run 

 curious tubes (the "trumpet hyphaB") which swell out at intervals, the swelling 

 being traversed in a transverse direction by a delicate sieve-plate. The stem 

 possesses a peripheral cambium-like zone, which adds each year a new zone of tissue 

 to the cortex. The stems, which are sometimes found much thicker than -one's 



Fig. 375. Laminariacese, with perforated fronds. 

 A S aru m G^clini (attar Biocreu*). . TtoUart&yUvn, cfatt, (after Po.tel, and Kuprecht). Both much reduced. 



thumb show in section a series of rings, reminding one of the annual rings of a 

 cotyledonous stem. A long ribbon-like form, L. saccharina, is also common on 

 >ur shores. I n other forms the frond is branched and often curiously appendaged 



375 ^ fl 

 (North 



( 



oceans nd on 



re P resented - " accompanying illustration (figs. 

 N rth Atkntic) has a 



n b th the fronds are 



totree - iike dimensi n 



Bu \ the tw most 



st of K ^ ^"^ ** B0ath " ni 



""' C nSIStS f a lon g stalk ' sometimes 



attaining a len^rr, nf , ' 1StS Ot a lon g stalk - sometimes 



i 300 metres, but in thickness not exceeding a penholder. To 



