68 Br^-ophyten. — Floristik, Geographie, Systematik etc. 



Wilson, M., On Spore Formation and Nuclear Division in 

 Mnium hornum. (Ann. of Bot. XXIII. p. 141 — 157. PI. X— XL 1909.) 



The resting nucleus both in vegetative and reproductive cells, 

 is characterised hy the presence of a ver}' large deeply stained 

 nucleolus; the nuclear reticulum is very fine and contains little or 

 no chromatin. The somatic and reduction divisions are normal. The 

 haploid and diploid chromosome numbers are twelve and six respecti- 

 vely. In the period of rest preceding the division of thespore mother- 

 celi, a body is budded oiT from the nucleolus; this persists until 

 after the first synapsis. With regard to the details of meiosis the 

 author writes: "The small size of the nuclei in the plant under 

 examination makes satisfactory elucidation of the events of chromo- 

 some formation difficult, but the evidence obtained confirms the 

 conclusions arrived at b}' Farmer and Moore." A. Robertson. 



Henriques, J. A., Tumboa Bainesii Hook. (Trabalhos da Acade- 

 mia de Sciencias de Portugal, l^r Serie. I. Lisboa, 1908. p. 91—95). 



Le Tumboa Bainesii [Welwitschia >nirabilis Hook, fil.) avait ete 

 profondement etudie par Sir J. D. Hooker. dans un memoire pu- 

 blic dans les Transactions of the Linnean Soc. II y a lä un, 

 point douteux sur l'origine de ce que Sir Hooker nomme crown. 



En disposant de quelques echantillons de cette singuliere plante 

 d'ages divers j'ai formule dans cette petite note une Interpreta- 

 tion, que je crois exacte. On a considere le corps de cette plante comme 

 non ramifie. Au contraire le corps se ramifie tres tot, donnant deux 

 rameaux en correspondance avec les deux feuilles cotyledonaires. 

 La crown est formee par ces deux rameaux, qui pendant son de- 

 veloppement se soudent entierement, formant dans les premieres 

 annees deux elevations, plus tard une surface convexe plus ou 

 moins irreguliere et au bout de bien des annees une surface concave. 

 Les feuilles permanentes sont inserees au fond d'une fente formee 

 par la tige et la partie libre des deux rameaux. Quatre gravures 

 completent cette description. J. Henriques. 



Holm, T., Observations on seedlings of North American 

 phaenogamous plants. (The Ottawa Naturalist XXII. p. 165 — 174, 

 235—244. plates IV, VII— VIII. Decbr. 1908. Febr. 1909.) 



A number of seedlings are described, and several figured, of 

 Monocotyledones and Dicotyledones. Among the former are mentioned 

 those of Agave, Sisyrinchium , Alisnia, Arisaema, Smi/ax, Comrne- 

 lynaceae, and some representatives of Cyperaceae and Gramineae. It 

 deserves notice that in Coix the so-called "stretched nodus" above the 

 scutellum does not show the structure of a node, but of an internode, 

 and the author adheres to the view that in the Gramineae , the scu- 

 tellum alone is the cotyledon, 'the epiblast the first leaf, and the 

 so-called "coleoptile" the second. The peculiar seedlings of Peltan- 

 dra and Orontiutn are described at lenght; both of these lack an 

 endosperm. Several types of dicotjiedonous seedlings are discussed, 

 showing the great diversitj^ in structure of the epigeic cotyledons 

 in Negimdo, Platamis, Vitis ,R/niS, Carpinus, Cornus, Celastrus, 

 Diospyros, Liriodendron , Catalpa, Ipoiuoea, Aralia etc. In Claytonia, 

 C. megarrhisa germinates with two cotyledons, while only one be- 

 comes developed in C. Virginica. Buds in the axils of the cotyledons 

 occur in Ceanothus, Gillenia etc., and from these shoots grow out 



