ferns, remarkable for the diversity of 

 the different parts of its fronds. The spe- 

 cies are generally referred to the Polypo- 

 diece group of true ferns, hut on account 

 of the sori being seated on a broad recep- 

 tacle, consisting not of a point on one 

 vein, but of a crowded network of fine 

 veinlets or little veins, they have been 

 sometimes placed along with Platy cerium, 

 in a small group called Platyceriece, in 

 which the same feature occurs. The fronds 

 are leathery in texture, with prominent 

 veins, merely pinnatifid, with the parts 

 broad at the base, but in the upper part 

 deeply divided into narrow or contracted 

 segments, which are fertile. The parts are 

 all articulated so as to separate spontane- 

 ously from the mamrib or rachis. The 

 sori are large and generally quadrangular, 

 closely set along each side of the costa, 

 each of them covering or seated on a flue 

 network of veins. They are without 

 indusia. The venation is very compound, 

 the veins and venules in the sterile parts 

 anastomosing freely in almost equal-sided 

 areoles, and enclosing free veinlets in the 

 ultimate spaces. There are only two spe- 

 I cies known, both of which are natives of 

 I the Philippine Islands. [T. MJ 



DRTPETES. A genus of Euphorbiacea? , 

 comprising a few West Indian and South 

 American trees or shrubs, which have al- 

 ternate oval or elliptical pointed leathery 

 leaves, and inconspicuous flowers arranged 

 in axillary fascicles, the males and females 

 on different plants. The males have a 

 calyx of four to six divisions, no petals, 

 and two to six free stamens; the females 

 have an ovary of one or two cells seated 

 in a fleshy disk. The fruit is a hard ellip- 

 tical dry drupe. The genus is nearly allied 

 to Hemicyclia, but the latter has numerous 

 stamens. [A A. B.] 



DRTPIS. A genus of Caryopliyllacea>, 

 distinguished by having a one-seeded utri- 

 cular capsule, which breaks across trans- 

 versely. D. spinosa, a Mediterranean 

 herb, has branched rigid fragile stems, 

 with opposite subulate leaves ending in 

 spines, and small rose-caloured flowers in 

 dense corymbose cymes, with only Ave sta- 

 mens in each. [J. T. S.] 



DRY ROT. "We are concerned with this 

 subject only so far as it may be the effect 

 of Fungi, or as calling those Fungi into 

 especial notice. As, however, Dry Rot may 

 be the effect of slow chemical combustion 

 as well as of Fungi, and the results are 

 much the same in either case, it is well 

 that any mycologist who may attempt 

 the investigation of the subject should be 

 aware of the fact. 



Dry Rot may be produced by various 

 species, as Polyporus hybridus, Tlielephora 

 puteana, Merulius lacrymans, &c. In oak 

 ir is generally due to the first, and in the 

 wood of conifers to the last. Different 

 kinds of timber, moreover, in tropical 

 countries have their own enemies, but 

 these at present have not been sufficiently 

 investigated. The spores of the Fungi 

 I 



i may be brought into the dock-yard with 

 the wood, in which case they are mostly 

 the i - esult of some ancient malady, and 

 may have remained dormant in the wood 

 altogether, or may have existed in the 

 shape of minute spawn. The foxy oak, 

 ; which is grown on old stools, owes its 

 colour to incipient decomposition accom- 

 panied by delicate spawn, and when ex- 

 ; posed to circumstances favourable to fun- 

 ! gal development, the perfect form of the 

 , fungus by which it was injured will soon 

 ! make its appearance. Elm trees are often 

 I strongly impregnated with spawn before 

 . they are felled, and we have lately seen 

 Polyporus ulmarms bursting forth from 

 the cut surface of an elm tree which 

 i fell a sacrifice to the spring gales of 

 I 1860, the whole wood being evidently af- 

 fected. 



i When the fungus attacks the surface, it 

 ! soon runs over it, and its spawn penetrates 

 j the wood, destroying all before it. The 

 ■ best remedy against Dry Rot consists in 

 careful selection of wood, perfect ventila- 

 tion, and patient seasoning, added to the 

 employment of such kinds of wood for 

 particular purposes as may be most suit; 

 | able to the situation they are intended to 

 occupy. Mineral salts may also be em- 

 ployed, but the remedy on which autho- 

 rities in the present day insist the most is 

 creosote, which has the property of coagu- 

 lating albumen, and making it enter into 

 combinations unfit for vegetation. It is, 

 however, found that where the proper 

 conditions have been secured, it is quite as 

 economical to do nothing, for even with 

 bad materials Dry Rot is not universal, and 

 with good, attended by proper precautions, 

 there will be little or no Dry Rot except 

 under accidental circumstances which are 

 i favourable to its progress. In damp situa- 

 [ tions with imperfect ventilation, even 

 should no fungus be present, decomposi- 

 tion is sure to take place, destructive to 

 the wood, and prejudicial to the health of 

 those who are constantly in its neighbour- 

 hood. In cellars and domestic buildings 

 where the fungus has not already com- 

 mitted too much mischief, it may be 

 effectually checked by washing it with a 

 strong solution of corrosive sublimate. 

 Where fungus does not exist, the remedy 

 is scarcely applicable when decay has com- 

 menced, though it may be useful in the 

 first instance. [M. J. BJ 



DUBOISIA. A name applied to an Aus- 

 tralian shrub, placed by Miers in Atropacea, 

 but by others referred to Scrophulariaccce. 

 Its flowers are in axillary clusters, white, 

 with a two-lipped calyx ; corolla funnel- 

 shaped, the limb five-parted; stamens five, 

 included within the corolla, four fertile 

 (two long, two short), and one rudimentary; 

 ovary with two many-ovuled compart- 

 ments ; fruit berry-like. [M. T. M.] 



DUBYiEA. A genus of Composites, 

 nearly related to Hieracium, but differing 

 in having beaked achenes. Of the three 

 known species, one with the habit of a 

 sowthistle is found in Australia ; another, 



