248 



THE DICTIONARY OF GARDENING, 



and unequally toothed at 

 1879. An elegant and 



Ptychosperma continued. 



apex, 1ft. to lift, long, dark green; petioles broadly sheathing 

 at the base. Stem somewhat stout, straight, h. about 60ft. 

 Queensland and New South Wales. A very elegant species, and 

 a most useful conservatory or cool greenhouse plant. See 

 Fig 317. SYNS. Archontophoenix Cunninphamiana (this name is 

 the correct one), Seaforthia elerjang (B. M. 4961). 



P. Kuhlii (Kuhl's). A synonym of Pinanga Kuhlii. 



P. Macarthuril (MacArthur-s). I. pinnate; leaflets arching 

 linear-oblong, truncate or oblique, an 

 apex, 4in. to Sin. long. New Guinea, 

 distinct palm. SYN. Kentia Macarthuri 



P Normanbyl (Normanby's). fl., inflorescence ovoid, axillary. 

 > 3~with a conical tip' about liin. long. I. 8ft to 10ft. 

 long. h. 40ft. to 60ft Australia. SYNS. Areca Normanbyl, Coco* 

 Normanbvi. 



P. Rumphii (Rumph's). A synonym of Drymophloeus olivce- 

 formis. 



P. rupicola (rock-loving). A synonym of Loxoeoceus rupicola. 



P. Seemanii (Seeman's).* 1. pinnate ; pinnae erose-dentate some- 

 what resembling those of a Caryota in appearance, and of a bright 

 green colour. Stem, when ful.y developed, about lin. in diameter, 

 strong. Fiji Islands, 1879. An elegant, dwarf-growing species. 



FUBERTTLOUS. Minutely pubescent. 



PUBESCENT. Softly downy or hairy. 



FT7CCINTA (named after an Italian botanist, 

 Puccini). A large genus of parasitic Fungi belonging to 

 the order Uredinece. In this order, the Fungi grow, with 

 a doubtful exception or two, on living plants, into which 

 they push their jointed mycelium. The reproduction is 

 always effected by conidia, or spores, produced on 

 branches from the mycelium, and never inclosed in 

 larger cells, as in Mould or in Pyrenomycetes 

 (which see). The conidia are usually crowded together 

 in masses, which, for a time, are protected by the 

 epidermis of the host-plant; but this generally becomes 

 torn, and the conidia are exposed. The conidia are 

 known to be of two, or even more, forms in almost all 

 the species in the order, and these forms are usually 

 very different from one another, affording very striking 

 examples of the phenomenon called " pleomorphism." So 

 different are they, that several genera were established 

 on what are now known to be only forms of the same 

 Fungi as had already received names tinder other 

 forms ; hence, much confusion has arisen, and this is 

 only gradually being overcome by careful and exact 

 observations. Even yet much doubt exists as to the 

 true relationships of many of the species. An attempt 

 will be made to render this part of the subject more 

 clear by describing what is now generally accepted 

 as the life-history of two or three of the more important 

 species of the genus Puccinia. The various forms of 

 conidia alternate with one another in the cycle of 

 development of each species, and experiments have led 

 to the belief that some species of Puccinia live on 

 different host-plants in the different stages of the cycle. 



The forms of reproductive organs met with in the 

 most complete cycles in the genus, e.g., that believed to 

 exist in P. graminis, are three or four in number. The 

 names employed to denote them were formerly given to 

 them when they were regarded as different species, 

 belonging to genera distinct from that now recognised 

 as the more mature condition (viz., Puccinia). The 

 forms are as follows: 



1. The JEcidium (old generic name), or Cluster-cup, in 

 the form of a cup, at first closed, afterwards open above. 

 The sides of the cup (peridium) consist of a single 

 layer of cells. The hollow is filled with closely-packed, 

 erect branches, arising from the mycelium, each of which 

 bears a chain or row of rounded, or angular, thin- 

 walled, yellow cells, which separate from one another, 

 and germinate readily, pushing out a mycelium thread. 

 On a leaf of the host-plant, the mycelium pushes through 

 a stoma, and produces the Fungus anew. The Cluster- 

 cups usually stand, as the name denotes, in clusters, on 

 thickened, discoloured tissues of the hosts, though, occa- 



Puccinia continued. 



sionally, they are scattered over the green parts without 

 causing much discoloration. They generally stand on 

 young stems and on the lower surface of leaves (see 



FIG. 318. LEAVES OF BERBERIS VULGARIS COVERED WITH ^ECIUIDM 

 BERBERIDIS (believed to be a stage in the development of 

 Puccinia graminin)a, ^Ecidium-patch on Leaf. 



Fig. 318), but may be on the upper surface also. On 

 the same mass of tissue as the cups, but, in general, on 

 the other side of the leaf, small, flask-shaped spaces 



FIG. 319. TRANSVERSE SECTION OP LEAF OF BERBERIS VULGARIS, 

 showing Spermogonia and jEcidium Berberidis, magnified con- 

 siderablya, ^icidium Cup just opened ; b, Thickened Tissue 

 of Leaf; c, c, ^Ecidium Cups fully opened, with Spores 

 dropping out ; , e. Skin of Leaf ; h, h, Outer Coat of JEci- 

 dium Cups ; sp, Spermogonia. 



(spermogonia) open by narrow mouths (see Fig. 319). 

 They are lined with branches of mycelium, bearing 

 extremely small, rod-like bodies (spermatia), which do 

 not seem to act as spores, and whose use to the Fungus 

 is doubtful. 



2. The Uredo (old generic name), is often developed 

 on the same mycelium as the former, but later; it 

 may grow only on a different host-plant. The uredo- 

 spores are not inclosed in a cup, or peridinm, but are 

 formed on the surface of convex masses of mycelium. 

 These masses are usually covered and protected by the 

 epidermis of the host-plant till the spores are ripe, when 

 the epidermis bursts. The spores are produced singly 

 on erect branches (see Fig. 320), and, when ripe, 

 fall off, and then are hardly to be distinguished from 



