294 Bryophyten. — Pteridophyten. — Floristik etc. 



Die einzeilschichtigen Haarspitzen an den Lappen der Involukren 

 sind hier noch viel länger als bei den Originalexemplaren von 

 Oberösterreich (11 Zellen lang). Matouschek (Wien). 



Hume, E. M. M., The Histology of the Sieve Tubes of 

 Pleridium aquilinum, with some Notes on Marsilia quadrifolia 

 and Lygodium dichotomum. (Ann. Bot. XXV[. o. 573 — 587. 2 pl. 

 April 1912.) 



The author gives an historical resume of the investigations on 

 the histology of sieve tubes. 



Pteridium aquilinum was fully investigated and a limited exa- 

 mination would point to a close resemblance to it of Lygodium 

 dichotomum and Marsilia quadrifolia. The sieve tubes and plates in 

 Pt. aquilinum provide for conduction all round the vascular Strand, 

 both in the node and internode, while in M. quadrifolia there is 

 little provision except at the nodes; the difference between the two 

 types is owing to the association of leaf, root and sporocarp at the 

 node in the latter species, no such regulär relation occurring in the 

 former plant. 



In finer histological details the sieve tubes correspond closely 

 with Pinus and the Angiosperms, e. g. in the presence of proto- 

 plasmic threads in early stages and the method of boring out to 

 form slime strings associated with callus. Differences are seen in 

 the ultimate total disappearance of the callus while the sieve tubes 

 are still functional, and in the presence and behaviour of the muci- 

 laginous droplets. The author suggests that the latter may be in 

 some way connected with the prolonged functioning of the sieve 

 tubes. There is no great development of callus and though the sieve 

 tubes tunction for years they are not blocked bj^ it in winter, pro- 

 bably because the rhizome is a subterranean organ. No callus was 

 detected on the frequent connections between sieve tubes and 

 parenchyma cells. E. de Fraine. 



Anonymus. Diagnoses Africanae. XLV. (Kew Bull. misc. 

 Inform. n°. 9. p. 356—361. 1911.) 



The new species described are Crassula globosa, N. E. Brown: 

 C. humilis, N. E. Brown; Mesembryanthemum dealbatum, N. E. Brown; 

 Chrysophyllum viridifolium , Woods and Franks; Stapelia similis, 

 N. 2. Brown; Penaea Candolleana, E. L. Stephens; Loranthus (con- 

 strictißori) crispatulus, Sprague; L.findens, Sprague; Jatropha Brock- 

 manii, Hutchinson; /. Confusa, Hutchinson. A. W. Hill. 



Anonymus. New Orchids: Decade XXXVIII. (Kew Bull, 

 misc. Inform. n°. 3. p. 131—135. 1912.) 



The following new Orchids are described by Mr. R. A. Rolfe 

 Pleurothallis repens, Dendrobium Nuthurnii, Bulbophyllum congestum, 

 Cirrhopetalum Micholitsii, Polystachya repens, Chondrorhyncha Lips- 

 combiae, Gongora Tracyana, Angraecum Andersonii, Physurus vali- 

 dus, Habenaria Dawei. A. W. Hill. 



Bonnet, E., Remarques sur la flore de la Mauritanie Oc- 

 cidentale. (Bull. Soc. bot. France. LVIII. p. 37—38. 1911.) 



Ces remarques sont relatives ä plusieurs especes publiees dans 



