778 SUMMARY OF CURRENT RESEARCHES RELATING TO 



AbietineEe, Cupressinese, and Sciadopitys the median region of the carpid 

 (bract of authors) is very small, while the two placenta are thick and 

 large, and are fused into one body. In the Podocarpeas, on the other 

 hand, and especially in Araucaria, the median region is well developed, 

 the fertile body small and more or less connate with the median region. 

 The barren leaf of Ophioglossum stands in precisely the same relation to 

 its fertile leaf as the barren leaf or median barren portion of the carpid 

 of Salisburia to its fertile portion. 



Although pleurospermy is far the most prevalent phenomenon in 

 Angiosperms, yet there are instances of antispermy, as in the true 

 central placentation of the Primulacese and Plumbagineae. Here there 

 are five tripartite carpids. The five median portions coalesce and form 

 the unilocular ovary with its single style or five styles ; the ten lateral 

 ovuliferous portions combine into a large central placentary body, 

 resulting evidently from the fusion of five autisj)ermic bodies. Anti- 

 spermy occurs also in the Juglandese, Loranthaceae, and Santalacese. 



Sensitive Stamens in Compositse.* — Prof. B. D. Halsted records 

 the occurrence of sensitive or elastic stamens in the following species of 

 Compositee : — Echinacea angustifolia, Heliopsis Isevis, Lepachys pinnata, 

 and RudhecMa hirta. The movements appear to be in all cases con- 

 nected with the distribution of the pollen. 



Bracteoles of the Involucre in the Cynaroeephalae.t — M. L. Daniel 

 describes the variations in the nature of the f<diar parenchyme in this 

 section of Compositse. The absence of stomates in the parts of the bract 

 placed in obscurity is a consequence of the sclerification of the epiderm, 

 and not of the obsciu*ity. The structure of the parenchyme depends 

 on the influeuce of the surroundings in which the bract or bracteole is 

 placed. 



Secund Inflorescence. | — Tracing the development of various instances 

 of this mode of inflorescence (excluding the scorpioid), Mr. T. Meehan 

 finds that it is common in perennial, but not in annual plants. He 

 believes it to be a comparatively recent stage in evolution, in which a 

 geotropic stem has assumed an erect condition, and arises from the 

 alternate twisting of the pedicels in contrary directions. 



Ovaries and Achenes of the Rose.§ — M. F. Crepin states that in 

 the sections of Bosse known as CaroUnse, the ovules, and later the 

 achenes, will be found situated at the bottom of the receptacle, while in 

 Cinnamomese the ovaries or their achenes will be found situated not only at 

 the bottom, but also to a certain height on the lateral walls. This affords 

 a character for separating the section CaroUnse from the Cinnamomese. 



Achenes of Coreopsis.] | — Mr. J. N. Eose describes the various forms 

 of achene (cypsela) to be found in Coreopsis, one of the Compositse. They 

 may be flat or somewhat four-sided, straight or curved, orbicular to 

 linear-oblong in outline, glabrous to pubescent, winged or wingless, 

 with entire or laciniate toothed margin, the apex truncate or emarginate, 

 the pappus of two awns or of teeth or scales, these generally hispid on 



* Bot. Gazette, xiv. (1883) pp. 151-2. Of. this Journal, ante, p. 544. 

 t Bull. Soc. Bot. France, xxxvi. (1889) pp. 133-43. Of. this Journal, ante, 

 p. 408. X Proc. Acad. Nat. Sci. Philad., 1889, pp. 53-6 (2 figs.). 



§ OR. Soc. Bot. Belgique, 1889, pp. 87-8. 

 II Bot. Gazette, xiv. (1889) pp. 145-51 (1 pi.). 



