V7 2 



Garden and Forest. 



[Number 447. 



the landscape. They come also to grace the most delight- 

 ful weather of our northern year. After our uncertain and 

 often disagreeable spring and the oppressive heats of sum- 

 mer these bracing days make life out of-doors a constant 

 delight, and one can imagine no more favorable conditions 

 for enjoying a garden than those furnished by an American 

 autumn. 



The Alpinum in the Botanic Garden of Tubingen. 



DURING a brief period of work in the Botanic Institute 

 at Tubingen during the summer, by the courtesy of 

 the director, Professor Vochting, I had ample opportunity 

 to examine the construction and become familiar with the 

 details of management of what, in many features, is the 

 most remarkable alpinum in the world. The Botanic Gar- 

 den, in which it is situated, lies in the north-eastern quarter 

 of the small university town of Tubingen, on both banks of 

 the Ammer, a small stream which empties into the Neckar, 

 a short distance away. The garden has an elevation of 

 about 1,000 feet, and near it are many hills covered with 

 forests of Pine, which rise 250 to 300 feet above it, while 

 to the southward, twenty miles away, the Swabian Alps 

 reach a height of 2,500 feet, in consequence of which the 

 night temperature falls far below that of the day. A lati- 

 tude of 4S 30' north, a low winter temperature of — thirty 

 degrees, Centigrade, a summer limit of twenty-five to twenty- 

 eight degrees, Centigrade, help to make a climate which 

 resembles that of southern Michigan in many respects. 



The alpinum is laid out in the north-western part of the 

 garden, on a rectangular plot of ground 190 feet in length 

 and nine feet in width, near a stone wall seven feet 

 high and parallel to its length. On this plot are piled the 

 rocks and soil necessary for the culture of the plants, in an 

 uneven ridge, which in one place is six feet in height. The 

 materials used were principally the native stalactitic lime- 

 stone and gravelly soil, and granite from the Black Forest 

 forty miles distant. The limestone is peculiarly suitable 

 for lower alpine plants and lithophytes, furnishing as it 

 does innumerable cavities for the reception of soil and 

 secure foot-hold for plants which cling directly to the rock. 

 It has been found that the species from the higher Euro- 

 pean Alps refused to grow on such rock, and hence the 

 granite was procured for the construction of the section 

 devoted to this group. The entire structure is in many 

 respects an admirable imitation of an east and west moun- 

 tain ridge. The northern side affords many shaded crev- 

 ices, and more or less shade to the whole is given by a 

 number of small trees near by. 



The most difficult problems which have confronted the 

 gardener in the construction and management of the 

 alpinum have been those connected with the water-supply. 

 The water content of such rocky soils is, of course, ex- 

 tremely small and needs almost constant replenishment. 

 In nature this is done by the water from the melting snows 

 above. Here it has been accomplished by a system of 

 branching pipes with many openings below and above 

 the surface, and a flow is allowed during the greater part 

 of the day. The drainage is carried away by cement con- 

 duits, and in one place forms an alpine lake eight feet in 

 length and five feet in width, which furnishes in its waters 

 and on the overhanging cliffs admirable conditions for a 

 very rich flora. Near the lake are growing several speci- 

 mens of Edelweiss, which here becomes somewhat longer- 

 stemmed than on its native cliffs, or in the alpine gardens 

 where it is cullivated to satisfy the thirst of the tourist for 

 mementos of "hazardous" ascents. 



Many of the alpine plants are quite intolerant of lime 

 salts and grow best on the granite rocks, but the water- 

 supply used here is taken directly from the city system 

 and is very richly charged with these salts, and, as a con- 

 sequence, the culture of some of the plants of the higher 

 slopes is impossible. This difficulty might be overcome at 

 some cost by a system of tanks for the storage of rain- 

 water, which would furnish exactly the natural conditions 

 for a large number of species. 



It is somewhat surprising to learn that on this area of 

 about 2,000 square feet more than 1,200 species are suc- 

 cessfully cultivated, almost all of which are perennials. In 

 some places three, and even four, kinds are grown on a 

 square foot of actual surface — a striking example of a form 

 of intensive cultivation. It must not be supposed, how- 

 ever, that none but alpine species are grown. A glance at 

 the list given below will show that many are at home far 

 southward in the temperate zone. As a matter of fact the 

 alpinum offers a wider range of conditions than any other 

 method of cultivation, and in some form similar to that 

 described might offer suitable conditions of growth for 

 species fairly representative of the flora of America north 

 of Texas, exclusive of trees. 



The following list is copied at random from the labels, 

 and comprises many rare species. In some instances a 

 species will be found growing, properly labeled, however, 

 outside of the section devoted to its habitat. Very naturally 

 the section devoted to the European Alps is richest in forms 

 growing at great elevations, as at present the opportunities 

 for European gardens to procure living specimens from the 

 higher American regions are somewhat limited. 



The following are the names of some plants grown in 

 the different sections of the alpinum : 



North America. — Sedmn stenopetalum, Draba incana, 

 D. borealis, D. rupestris, Geum triHorum, Saxifraga cuneifolia, 

 S. Pennsylvania, S. bronchialis, S. stelleriana, Heuchera pu- 

 bescens, H. sanguinea, Potentilla villosa, Cypripedium mon- 

 tanum, C. arietinum, C. pubescens, C. candidum, C. spectabile, 

 C. acaule, Phlox nivalis, CEnothera pumila, Dicentra Cana- 

 densis. 



Asia : Himalayas. — Sedum Kamschaticum, S. Asiaticum, 

 Primula aunculata, P. Japonica, P. denliculata, P. erosa, Asler 

 alpinus, var. Himalayensis, Androsace sarmentosa, A. lan- 

 guinosa, Gentiana Thibetica, G. septemifolia, Rehmannia 

 Chinensis, Leontodon Himalayensis, Hepatica Valdensis, 

 Artemisia stellerianum, Polygonum Brunnonis. 



Europe: Alps. — Soldanelia alpina, S. pusilla, S. minima, 

 Gymnnadema odorotissima, Sempervirens crassicaulis, Cys- 

 topteris alpinus, Achillea alpina, Ranunculus alpestris, Erige- 

 ron neglectum, E. alpestris, Chrysanthemum alpinum, Pinus 

 pumila, P. cembra, Saxifraga aretiodes, S. densa, Campanula 

 thyrsoides, Mulgedium alpinum. 



Philadelphia, Pa. D. T. MacDoilgCll. 



The Sand Dunes of Northern Indiana and their 

 Flora.— II. 



ONE of the first plants to appear on the higher dunes 

 is the Bug seed, Corispermum hyssopifolium, an an- 

 nual, somewhat succulent, bearing a thin, fiat, winged 

 seed, which is readily moved about by the wind. Its low 

 stature and sparse narrow leaves catch but little of the 

 wind, so that it is easily established. In more favorable 

 localities it has a dense round head, and when torn from 

 the ground in autumn becomes a Tumble-weed, which 

 helps still further to disseminate it. The first of the Grasses 

 to start, and among the earliest plants to gain a footing, 

 a*re Calamagrostis longifolia, Panicum virgatum and Am- 

 mophila arundinacea, the Sea-sand Reed. The last is more 

 common at lower levels among the beach-sands, but it 

 comes up the sides of the higher dunes near the shore, and 

 is found upon their tops. Grasses which come in later are 

 Andropogon scoparius, A. fureatus, and the nearly allied 

 Chrysopogon nutans, always a welcome sight, with its 

 graceful panicles of russet silky spikes. Elymus Cana- 

 densis, especially the variety glaucifolia, frequently grows 

 with the Calamagrostis and the Sea-sand Reed, and shows 

 very large curving or nodding spikes of pale green. To 

 these Grasses will be added subsequently species of Sporo- 

 bolus, and in open but more sheltered places in the woods 

 the small annual, Festuca tenella, thickly covering the 

 ground in spring and early summer with a dense growth of 

 low wiry stems. Common also are two closely related 

 and pretty species, Eatonia obtusata and Koeleria cristata. 

 Very interesting, from the behavior of its fruit, is theTriple- 

 awned Grass, Aristida tuberculosa, its awns conveniently 

 arranged to anchor the seed and force it into the sand as 



