Howellia aquatilis (Campanulaceae) is a rare aquatic plant considered endangered throughout its range in the Pacific Northwest. Howellia appears to have a narrow ecological amplitude, occurring only in temporary ponds suwounded by trees. Anatomical observations of developing flowers indicate a restrictive breeding system approaching obligate self‐fertilization. We used protein electrophoresis to examine the genetic structure of four populations from throughout the range of species. Eight enzymes encoded by 18 putative loci showed no variation, either within or among populations. Howellia's small ecological amplitude and lack of genetic variability lead us to believe that the species is prone to extinction A conservation strategy for this species should include protection of ponds that are currently inhabited by Howellia as well as ponds that will become appropriate habitat in the future. To insure against large‐scale environmental perturbations, multiple pond clusters throughout the range of the species should be protected.

Flagella of living sperm of the ferns, Lygodium japonicum (Thunb.) Sw. and Marsilea vestita Hook, and Grev., beat three dimensionally with a continuous traveling helical wave. The wave is propagated from base to tip of the flagellum. Flagella of Lygodium and Marsilea complete 65 and 30 beat cycles per sec, respectively. Each flagellum circumscribes an open conicoid oriented in a latero‐posterior direction. Only dead sperm have anteriorly directed flagella as illustrated in plant morphology textbooks.

When antheridia of gametophytes of Equisetum hyemale L. are placed in water, only spermatid cells are released. These spermatid cells have from 6–12 fibrils radiating from 2–4 loci on the cell wall. One sperm is released from each spermatid cell. With high speed cinemicrography, it can be shown that sperm flagella beat three dimensionally with a continuous, traveling helical wave. A flagellar beat cycle is completed every 0.03 sec. In water the sperm swim rapidly at a rate of 300 μ per sec and traverse a helical path of long wavelength and shallow amplitude. Calcium is essential for normal locomotor behavior. When calcium is chelated by ethylenediaminetetraacetate (EDTA), the sperm spin in place. All other monovalent and divalent ionic solutions tested cause the sperm to swim abnormally. Monovalent ionic solutions prevent the drastic change in sperm mobility patterns resulting from chelation by EDTA.

The amylases of developing barley seeds (Hordeum vulgare L. cv. Himalaya) were investigated by colorimetric and electrophoretic methods. Maxima of amylolytic activity appeared in the aleurone layers and-starchy endosperm at 5 and 20 days after anthesis. Amylase from 5-day-old aleurone layers could be separated into four rapidly moving bands with a-amylase activity. By 20 days the four bands had been replaced by seven bands of medium mobility. These seven bands of amylase were electrophoretically identical to those observed when mature aleurone layers are treated with gibberellic acid. Immature aleurone layers failed to respond to exogenous gibberellic acid. In the starchy endosperm the seven bands of medium mobility were also present. Calcium-dependent alterations in the electrophoretic mobility and activity of particular bands occurred during the maturation of the starchy endosperm. Treatment of the immature starchy endosperm with papain yielded four forms of 8-amylase. Amylases produced by the mature aleurone layers of barley have been investigated extensively (1,3,4,7,8,12,17,18 The starch solution for the amylase assay was prepared by adding 150 mg of nonsolubilized potato starch, 600 mg of KH2PO4, and 151 mg of CaClh to a 100-ml volume of water.The starch suspension was boiled for 1 min, cooled, and centrifuged at 10,000g for 15 min. The clear supernatant was used for the enzyme assay. An aliquot of enzyme (0.1 ml) was added to 0.5 ml of the starch solution in a 18-X 150-mm test tube, and the reaction was allowed to proceed for a suitable time (2-10 min). Starch hydrolysis was stopped with 1.0 ml of iodine reagent. The iodine reagent was made by adding 0.15 ml of an iodine stock solution (6 g of KI and 600 mg of L. in 100 ml of water) to 50 ml of 0.05 N hydrochloric acid. After the reaction had been stopped, water was added to the reaction mixture to give a final volume of 3 ml, and the absorbance was read at 620 nm with a Coleman colorimeter. The change in absorbance was proportional to the amount of amylase present.Seed imbibition and isolation and incubation of aleurone layers from mature seeds were performed as described by Chrispeels and Varner (3).Acrylamide Electrophoresis. Methods for the electrophoresis of amylase were followed as described by Scandalios (16) Enzyme samples from the incubation medium or from tissue extracted with 0.2 M NaCl were absorbed into small paper wicks. These wicks were inserted into a slit 4 cm from one edge of the tray. Electrophoresis was accomplished with a voltage gradient of 12 to 13 v/cm for 22 hr at 5 C. The wicks were removed after 0.5 hr. The gel was covered during electrophoresis with cellophane (Handiwrap) to retard desiccation. After electrophoresis, the gel was incubated in a starch solution (I % Lintner starch in 40 mm sodium phosphate or tris-malate buffer, pH 7.0) at 25 C for 5 hr. Bands of amylolytic activity were visualized by immersing the incubated gel in a I2-KI solution for 20 to 30 min.Amylose Hydrolysis. For end product analysis of amyla...