OLIVEE ON THE STEM OF DICOTYLEDONS. 315 



paiiied by annular vessels. True spirals are not found either 

 sheathing the medulla or in the wood. The wood-bundles which 

 are traversed by extremely numerous and very narrow medullary 

 rays, are composed of stout, thick-walled, dotted fibres, amongst 

 which are scattered much longer, tubular, attenuated cells, with 

 thick, transparent walls destitute of markings. Opposite and 

 external to each of the eight ligneous fascicles are isolated bundles 

 of liber, plunged in the green parenchyma of the bark. These 

 liber-bundles, which do not increase with age, are attenuated 

 towards the extremities of each interuode of the stem, and are 

 not continuous through the articulations, where the wood-fibres 

 of the contiguous iuternodes interlace. M. Dutrochet was mis- 

 taken in supposing the joints to be separated by a transverse 

 layer of cellular tissue. — Willshire (Dr.) Contributions to Struc- 

 tural Botany, Ann. Nat. Hist. IS 42, ix. 84i. Confii^matory of 

 Decaisne's Observations on the Structure of the Nodes. — Pitra, 

 A. Ueber die Anheftungsweise einiger phanerogamen Parasiten 

 an ihre Nahrpflanzen. Bot. Zeit. 1861, 53. With figs. — Myzo- 

 dendron. E.. Browoi, Linn. Trans, xix. 231 (in note). — Dr. J. D. 

 Hooker in ' Elora Antarctica,' ii. 289, tab. cvii. ; Ann. Sc. Nat. 

 Ser. iii. 5, 193. In the important essay on the structure of this 

 genus a full account is given of the internal anatomy of M, 

 punctulatum and M. hrachystacliyum , also brief notices of that 

 of M. quadrifloruvi and M. linear if olium. The first two species 

 named difter so remarkably in structure, " that no one, from 

 an examination of their wood alone, would hesitate in pro- 

 nouncing them to be plants widely separated in a natural 

 system." In M. ptmctulatum there is no pith ; the axis is 

 formed of a dense, thick- walled proscnchymatous tissue of very 

 small cells, from which wedge-shaped plates are projected after 

 the manner of medullary rays into the surrounding tissue (the 

 zone usually occupied by prosenchyma in woody dicotyledons) 

 which is wholly, or almost wholly, formed of elongated tubes of 

 nearly equal diameter, dotted, annular, transversely barred, or 

 containing more or less interrupted spirals. Ordinary prosenchyma 

 and true spiral vessels were not observed either in the medullary 

 sheath or iimer portion of the annual layers. — -M. hradiystachyivm 

 has a pith of soft cellular tissue communicating with the bark by 

 broad medullary rays. These are separated by woody plates in 

 two concentric series, formed almost entirely of scalariform tissue, 

 with, sometimes, prosenchym ; the series are separated by a broad 

 belt of parenchyma. The formation of the two concentric wood- 

 zones is described at length (p. 299). — Chatin, Gr. A. Anat. Comp. 

 d. Vegetaux (Parasites), tab. Ixxiv.-vi. The anatomy of 3£. 

 hr achy st achy um, M. ohlongifolium, M. lineari/olium and M. punc- 

 tulatum, with sections showing the attachment of the parasite to 

 Fagiis. The text has not reached us. — Arceuthohiuvi oxijcedri. 

 Chatin, Gr. A. Anat. Comp. d. Yeget (Parasites), tab. Ixxvii. Text 

 N. H. R.— 1862. Z 



