238 MORPHOLOGY, ETC., VASC. PLANTS [BoT. Absts., Vol. IX, 



14S3. Bradley, Cornelius Beach. The phyllotaxy of Phoenix canariensis. Torreya 

 21: 37-44. PI. 1-2, 1 chart. 1921. — A study of ornamental specimens of Phoenix canariensis 

 grown in and about Berkeley, California, shows that the leaf arrangement is not of a single 

 and stable pattern. Each tree has passed through several distinct phases of phyllotaxy. 

 Three zones representing regular patterns, the 5-, 13-, and 34-ranked, are recognized, and the 

 intervals between are occupied by 2 groupings not belonging to any of the ordinary alignments. 

 The interfoliar arc is gradually changed so as to build up these transitional formations, causing 

 the vertical ranks to swerve in the direction of the primary spiral. This rotation of the pattern 

 is continued until some one of the secondary ranks becomes vertical, after which another regu- 

 lar pattern begins. The chart illustrates the sequence of patterns in the 5 phyllotactic zones. 

 — /. C. Nelson. 



1484. Briquet, J. La structure foliaire des Hypericum a feuilles scleromarginees. [Foliar 

 structure of Hypericum species having leaves with indurated margins.] Compt. Rend. Soc. 

 Phys. et Hist. Nat. Geneve 36: 75-79. 1919. — In certain species of Hypericu7n, the leaves are 

 reinforced along their margins by a thickening that unites with the veins in a way suggesting 

 that it constitutes a portion of the fibro-vascular system. Three species, H. pimelaeoides 

 PI. and Lind, H. cordiforme St. Nil, and H. connatvm Lamk. were studied to determine whether 

 such a condition actually occurred. The thickenings were found to be composed in some cases 

 of an exaggerated development of epidermal covering; in other cases, of greater development 

 of collenchyma. The function appears to consist in permitting the leaf to retain its form 

 during periods of intense transpiration and to resist tearing. — Charles Drechsler. 



1485. Briquet, J. Les trichomes foliaires des Centauries Phrygiees. [The foliar tri- 

 chomes of species of Centaurea.] Compt. Rend. Soc. Phys. et Hist. Nat. Geneve 36 : 96-102. 

 1919. — The hairs of Centaurea spp. consist of 2 parts; the foot, composed of 2 or more relatively 

 broad cells, and the flagellum, composed of a single elongated slender cell, the contents of which 

 dies soon after its development. The flagellum is often early caducous, leading to a variety 

 of conditions described as harsh, hirsute, etc., although where it remains attached a tomentose 

 condition obtains. The shedding of the flagellum is related to a fold along its base. Trichomes 

 are described in detail for C. procumbens Balb., C. Jordaniana Godr. and Grev., C. pectinata 

 L., C. uniflora, C. phrygia L. emend., C. rhaetica Moritzi, C. trichocephala, C. hyssopifolia 

 Vahl., C. linifolia Vahl., and C. antennata Duf. In general, 3 tj'pes may be distinguished, 

 1 with a cylindrical foot, a 2nd with a conical foot, and a 3rd with the foot irregular. From 

 an ecological standpoint the trichomes serve to reduce evaporation while the leaf is young by 

 surrounding the leaf in a dead air space confined within the cottony or tomentose layer formed 

 by the flagella. — Charles Drechsler. 



1486. Campbell, Douglas Houghton. The gametophyte and embryo of Botrychium 

 obliquum Muhl. Ann. Botany 35: 141-158. PI. 7, 11 fig. 1921.— The gametophyte of J3oiryc;i- 

 ium ohliquum is similar to those of other species of the genus. The embryo, however, differs 

 in several important respects from those of the other 2 species, B. Lunaria and B. virginianum, 

 which have been studied and which with B. ohliquum represent the 3 types of adult sporophytes 

 found in the genus. It differs in the endogenous origin of the root, in the bipolar arrangement 

 of cotyledon and root, and especially in the presence of a suspensor. The embryo is in fact 

 much more like those of some species of Ophioglossum and Danaea than it is like those of other 

 species of Botrychium. It has previously been shown that the embryos of B. Lunaria and jB. 

 virginianum are very different from each other. The author believes that if further investiga- 

 tion shows that other species of the Ternatum group agree with B. ohliquum in regard to the 

 embryo, there is ample reason for separating off this section as a new genus, and also that 

 B. virginianum differs sufficiently from the other species to deserve generic rank. The present 

 genus would thus be divided into 3. The development of the embryo, including the apical 

 regions of stem, cotyledon, and root, as well as the vascular system, is worked out in detail. — 

 W. P. Thompson. 



1487. Collins, Marjorie I. On the structure of the resin-secreting glands in some Aus- 

 tralian plants. Proc. Linn. Soc. New South Wales 45: 329-336. Fig. 1-12. 1920.— A descrip- 



